2023 USDA Plant Hardiness Zone Maps Out

[Allen]

OK OK we all know the zones have flaws, yada yada but look and see if your zone went up.

Click on map or put in zip code for your plant zone.

Mine went from 7A to 7B

https://planthardiness.ars.usda.gov/

For noobs the plant zone is used to give a idea of what plants can be grown where you live and it is a 30 year average of the lowest temp recorded for each year.   For example my zone is now 7B which indicated the average low over the past 30 years is between 5F-10F.  But I had a -1F last year that also goes in that average and might kill some palms.  

 

Comparison of 2023 vs 2012 (Newest previous) Map

Edited November 15, 2023 by Allen

[DAVEinMB]

I'm still listed as 8b but that 9a is tickling my feet about 45 miles south

[BigBilly]

54 minutes ago, Allen said:

OK OK we all know the zones have flaws, yada yada but look and see if your zone went up.

Click on map or put in zip code for your plant zone.

Mine went from 7A to 7B

https://planthardiness.ars.usda.gov/

For noobs the plant zone is used to give a idea of what plants can be grown where you live and it is a 30 year average of the lowest temp recorded for each year.   For example my zone is now 7B which indicated the average low over the past 30 years is between 5F-10F.  But I had a -1F last year that also goes in that average and might kill some palms.  

 

Comparison of 2023 vs 2012 (Newest previous) Map

I'm on the border of 7B and 8A now , Guess i will try those palmettos

 

Edited November 15, 2023 by BigBilly

[ZPalms]

I'm now according to this map 8b now which is cool, I'll still plant like I'm in 8a with the normal expected variables. Very neat though 🤠👍

Just curious though does this actually mean anything for plants or Is this just saying since I'm newly 8b that a plant may live but no guaranteed at this very moment?

[Fusca]

I don't pay much attention to these maps - it's interesting to me that the newest map for 2023 is using weather data from 1991-2020 so the recent polar vortex events of the last few winters are not factored in.  This map reflects some of the warmest winters in Texas and perhaps other areas as well.  I'm more interested to see what the next map looks like that includes data from February 2021 plus other more recent unusual cold events.

[BigBilly]

Just now, Fusca said:

I don't pay much attention to these maps - it's interesting to me that the newest map for 2023 is using weather data from 1991-2020 so the recent polar vortex events of the last few winters are not factored in.  This map reflects some of the warmest winters in Texas and perhaps other areas as well.  I'm more interested to see what the next map looks like that includes data from February 2021 plus other more recent unusual cold events.

Hey, we only gotta wait 7 more years! 

[Allen]

1 hour ago, ZPalms said:

I'm now according to this map 8b now which is cool, I'll still plant like I'm in 8a with the normal expected variables. Very neat though 🤠👍

Just curious though does this actually mean anything for plants or Is this just saying since I'm newly 8b that a plant may live but no guaranteed at this very moment?

This is based on 30 years data so with palms it is still best to look at the lows your palms can handle and look at the absolute lows during the time period you feel comfortable with

1 hour ago, Fusca said:

I don't pay much attention to these maps - it's interesting to me that the newest map for 2023 is using weather data from 1991-2020 so the recent polar vortex events of the last few winters are not factored in.  This map reflects some of the warmest winters in Texas and perhaps other areas as well.  I'm more interested to see what the next map looks like that includes data from February 2021 plus other more recent unusual cold events.

Well it's pretty easy to do individual cities if you have access to weather data.  I just put them in a spreadsheet and have it average it.   I'm glad you brought up the 1991-2020 data

Tennessee got really bumped up compared to other states?? @teddytn did you go to 7B??

Edited November 15, 2023 by Allen

[teddytn]

16 minutes ago, Allen said:

This is based on 30 years data so with palms it is still best to look at the lows your palms can handle and look at the absolute lows during the time period you feel comfortable with

Well it's pretty easy to do individual cities if you have access to weather data.  I just put them in a spreadsheet and have it average it.   I'm glad you brought up the 1991-2020 data

Tennessee got really bumped up compared to other states?? @teddytn did you go to 7B??

Yup 7b here! Now I can grow palms like all the cool guys lol. We talked about this before and most winters have been tracking that way, except last winter….😅

[Allen]

17 minutes ago, teddytn said:

Yup 7b here! Now I can grow palms like all the cool guys lol. We talked about this before and most winters have been tracking that way, except last winter….😅

@teddytn That trunked Sabal might be there yet if we get some luck

Also what is interesting on the data is so much change with a overlap of  14 years 1991-2005

Edited November 15, 2023 by Allen

[RFun]

I won't comment on this.  Just make your own observations in your local area (however small it is), as always.

Edited November 15, 2023 by RFun

[Xerarch]

I don’t see an interactive version of this one like the 2012? Hopefully that is coming, that was nice. 

[Allen]

Just now, Xerarch said:

I don’t see an interactive version of this one like the 2012? Hopefully that is coming, that was nice. 

ON a PC I can scroll in and out and see street level detail if you follow the link?  Is that what you mean?

 

https://planthardiness.ars.usda.gov/

[N8ALLRIGHT]

Woohoo, now I'm 6b, bring on the coconuts

[Xerarch]

10 hours ago, Allen said:

ON a PC I can scroll in and out and see street level detail if you follow the link?  Is that what you mean?

 

https://planthardiness.ars.usda.gov/

I haven’t actually had the chance to mess with it on PC yet so that may help. In the old days they used to have a nicer interactive version of the 2012 map than what we have available now, not only could you scroll in and out but you could control the opacity level so you could see through the colors to see areas of water, geographic features etc that were covered by the colors. You could also click on any point in the map and it would tell you the calculated value for that exact spot, based on whatever algorithm of course so it wasn’t perfect, but it was still nice to see and take into consideration. For example, when that map was available if I clicked on top of my house, it gave me an estimated value of 29.7 degrees, narrowly missing the 10a threshold.  Now the map has  me in 10a, but it would be cool to see that estimated number, 30.1? 34.9? By my own calculations I’m a lot closer to the lower threshold than the upper but I would like that functionality back. 

[ChicagoPalma]

Yay, while im rated zone 6a/6b, but my winters say the other! But that means technically Im in the region where palms can grow! Needles and sabal minors unprotected.

[Allen]

1 hour ago, Xerarch said:

I haven’t actually had the chance to mess with it on PC yet so that may help. In the old days they used to have a nicer interactive version of the 2012 map than what we have available now, not only could you scroll in and out but you could control the opacity level so you could see through the colors to see areas of water, geographic features etc that were covered by the colors. You could also click on any point in the map and it would tell you the calculated value for that exact spot, based on whatever algorithm of course so it wasn’t perfect, but it was still nice to see and take into consideration. For example, when that map was available if I clicked on top of my house, it gave me an estimated value of 29.7 degrees, narrowly missing the 10a threshold.  Now the map has  me in 10a, but it would be cool to see that estimated number, 30.1? 34.9? By my own calculations I’m a lot closer to the lower threshold than the upper but I would like that functionality back. 

I just played with it on PC and it does everything above except give the exact calculated temp.  It has layers on/off, zoom to look at your house and click on any spot to see zone even on top of your house

[MarcusH]

I went from 8b/9a to 9a . Average temperatures were measured from 1991 to 2020. We have seen severe winter cold fronds the last 3 years that we're at least an entire zone colder in a lot of regions  Climate is changing and a lot of those polar vortex aren't fully understood.  You plant Queen palms in Houston I guarantee you they won't be there for a long time.  That new update is a joke and misleading .

[DAVEinMB]

14 hours ago, ZPalms said:

Just curious though does this actually mean anything for plants or Is this just saying since I'm newly 8b that a plant may live but no guaranteed at this very moment?

If your zone has gone up it just means that historical temperature data shows a warming trend over the observed time frame.

Now that you're designated 8b will you never see an 8a winter, no. Will they be fewer and farther between, yes. 

[Las Palmas Norte]

19 minutes ago, MarcusH said:

I went from 8b/9a to 9a . Average temperatures were measured from 1991 to 2020. We have seen severe winter cold fronds the last 3 years that we're at least an entire zone colder in a lot of regions  Climate is changing and a lot of those polar vortex aren't fully understood.  You plant Queen palms in Houston I guarantee you they won't be there for a long time.  That new update is a joke and misleading .

Yes. The indicator plants speak louder than office data, or what ever has been used to formulate these results. These zones only address part of the gardening equation, & do not address climate.

[scarecrow]

Zone creep is real. https://e360.yale.edu/features/redrawing-the-map-how-the-worlds-climate-zones-are-shifting#:~:text=Plant Hardiness Zones are moving,United States Department of Agriculture.

Edited November 15, 2023 by scarecrow

[Silas_Sancona]

2 hours ago, Xerarch said:

I haven’t actually had the chance to mess with it on PC yet so that may help. In the old days they used to have a nicer interactive version of the 2012 map than what we have available now, not only could you scroll in and out but you could control the opacity level so you could see through the colors to see areas of water, geographic features etc that were covered by the colors. You could also click on any point in the map and it would tell you the calculated value for that exact spot, based on whatever algorithm of course so it wasn’t perfect, but it was still nice to see and take into consideration. For example, when that map was available if I clicked on top of my house, it gave me an estimated value of 29.7 degrees, narrowly missing the 10a threshold.  Now the map has  me in 10a, but it would be cool to see that estimated number, 30.1? 34.9? By my own calculations I’m a lot closer to the lower threshold than the upper but I would like that functionality back. 

That's the one thing missing ..so far... with this release of the maps..  Yes, you can get in closer, but, you could bet in ..a lot closer.. w/ the interactive map from 2012.  Hopefully, that option will be implemented with this update asap.

I'm also awaiting Mexico updating it's map ..if -or when- they do...

Coming back to locally,  ..updated map is on par for what i've seen here in AZ  ...though there are some misses..  For one, yes, an expansion of 10 around the valley is obvious. That said, i'd have thought everything within -at least the loop 202 would have been designated 10 ..Basically is now. ( Map screen shot #2 )  The 9a/ 9b line in the East Valley has shifted out of Maricopa Co.,  to ~roughly~ south of the Gila River in the 2023 update as well.

Thinking on the future,  90% sure that ..if there are no serious setbacks, all of the valley will be 10 by the next update. Possible too areas near Boyce / areas just east of Florence will be sprinkled w/ 10 as well.

FYI: " Dots " represent the following:

Green: = Chandler

Red: = Gilbert

Blue: Queen Creek

White = Map #2 / Magenta = Map #1: = Apache Junction

Purple; = Roughly where Boyce Thompson is ( Map #2 )






Tucson is the biggest change, though the area of 9A they held onto along the 10 between roughly where the 77 meets the 10, and just north of ..say Tangerine RD should be 9B.  That said, not too much development in that area atm, so, holding onto the cooler designation -for now- has merit.  ..As do the ..very subtle shifting of the 8a/b - 9a areas south of Tucson.

Going with  the same thoughts - for - the - future, anticipate another big expansion of 9B down there ..maybe a speck or two of 10 close to downtown by the next map update ..or the one after. 

Most areas of 8 south of Tucson, and the specks of 6b - 7b atop Mt. Lemmon / Wrightson, the highest peaks in the Huachucas, and atop Mica will be gone by that  time as well.  Nogales will be 9a ..with a few possible specks of 9b creeping in.

White dot: = Agua Calente Park ( Cold spot on the east side of Tucson, where the " Washingtonia Oasis " is  )

Green Dot = Las Cienegas / Sonoita

Red and Orange Dots = Corona De Tucson area ( Red )  / Green Valley / Sahuarita ( Orange dot )

Blue = Patagonia.. 

[Xenon]

1 hour ago, MarcusH said:

You plant Queen palms in Houston I guarantee you they won't be there for a long time.  That new update is a joke and misleading .

30 years is enough for me 😍, why so negative? 😂

Really enjoy all the queens in New Orleans and Jacksonville too also on borrowed time, better than no time 😂

[Silas_Sancona]

13 minutes ago, Xenon said:

30 years is enough for me 😍, why so negative? 😂

Really enjoy all the queens in New Orleans and Jacksonville too also on borrowed time, better than no time 😂

A major case of the big, bad, ( n' scary ) " What - if - Itis " perhaps?..  

[MarcusH]

51 minutes ago, Xenon said:

30 years is enough for me 😍, why so negative? 😂

Really enjoy all the queens in New Orleans and Jacksonville too also on borrowed time, better than no time 😂

I'm not negative or pessimistic just saying that palms and other plants don't care about average temperatures.  It's the ultimate low that's where we should focus on. 20 to 30 years might be good for you but so far we have seen 2 severe cold fronts in the 2020s (2 in 3 years) . To me personally that's one good reason not to care about palms that can't handle our lows.  If everyone would care about that we wouldn't see the large amounts of dead Robustas in Houston and San Antonio.  Even 2 years after Palmageddon there's still a lot of evidence.  Dead palms look ugly and ruin the landscape.  Should have planted sabals or Filiferas instead.  

[DTS]

lets go im 6b now

[MarcusH]

2 hours ago, DAVEinMB said:

If your zone has gone up it just means that historical temperature data shows a warming trend over the observed time frame.

Now that you're designated 8b will you never see an 8a winter, no. Will they be fewer and farther between, yes. 

Yes fewer cold fronts in future but they're still severe in some cases. 

[knikfar]

We moved from 7b to 8a here in Raleigh. But we still can't grow butia without having to protect them a few days every year. So this doesn't really mean much to me. 

[Xenon]

1 hour ago, MarcusH said:

I'm not negative or pessimistic just saying that palms and other plants don't care about average temperatures.  It's the ultimate low that's where we should focus on. 20 to 30 years might be good for you but so far we have seen 2 severe cold fronts in the 2020s (2 in 3 years) . To me personally that's one good reason not to care about palms that can't handle our lows.  If everyone would care about that we wouldn't see the large amounts of dead Robustas in Houston and San Antonio.  Even 2 years after Palmageddon there's still a lot of evidence.  Dead palms look ugly and ruin the landscape.  Should have planted sabals or Filiferas instead.  

I'm not going to start planting royals everywhere after 2 mild winters, why is that any different from planting based only on two of the coldest years when the long term average (30-50+ years) is much higher? This is a palm growing group after all, most of us don't have the luxury of growing in Hawaii so there is always some degree of risk whether cold, heat, hurricanes, (volcanos?) etc. 

Three years ago there were old queens from the 90s and suddenly now they're impossible to grow? Doesn't sound very logical to me. I plant everything from Sabal to queen, king, and zone 10. Keeps the hobby interesting!

Hope your queen sticks around for a few more seasons! Would be a shame to remove it early, it might surprise you. There's always time to replace it with something else when it does croak.

[DTS]

and finally, parts of michigan is zone 7a!

[MarcusH]

1 minute ago, Xenon said:

I'm not going to start planting royals everywhere after 2 mild winters, why is that any different from planting based only on two of the coldest years when the long term average (30-50+ years) is much higher? This is a palm growing group after all, most of us don't have the luxury of growing in Hawaii so there is always some degree of risk whether cold, heat, hurricanes, (volcanos?) etc. 

Three years ago there were old queens from the 90s and suddenly now they're impossible to grow? Doesn't sound very logical to me. I plant everything from Sabal to queen, king, and zone 10. Keeps the hobby interesting!

Hope your queen sticks around for a few more seasons! Would be a shame to remove it early, it might surprise you. There's always time to replace it with something else when it does croak.

I have two Queens in the ground ,doing good so far ( knocking on wood) .

I have no problem protecting it it's just the recovery process took ages . If this winter doesn't burn the fronds it's going to stay in the ground if not I'm going to replace the Queens. I'd like to enjoy the looks of a full crown not looking at 3 fronds in late June LOL I know what you're saying Jonathan 😉.  

[MarcusH]

1 minute ago, MarcusH said:

I have two Queens in the ground ,doing good so far ( knocking on wood) .

I have no problem protecting it it's just the recovery process took ages . If this winter doesn't burn the fronds it's going to stay in the ground if not I'm going to replace the Queens. I'd like to enjoy the looks of a full crown not looking at 3 fronds in late June LOL I know what you're saying Jonathan 😉.  

Here's my 16F survivor , looking good now working on its 6th frond. 

 

[bgifford]

So close to a Zone upgrade. literally 10 miles away from going from 6b to 7a. Weird thing is that  the area that went to 7a had colder temps than where I live (at least very recent years).

[RFun]

5 hours ago, Allen said:

I just played with it on PC and it does everything above except give the exact calculated temp.  It has layers on/off, zoom to look at your house and click on any spot to see zone even on top of your house

Of course, this map doesn't factor in that a backyard could conceivably have 3 different zones in it lol.  It's missing a lot of those detailed measurements in cold sink areas, up by buildings or near bodies of water, etc.

Edited November 15, 2023 by RFun

[Allen]

17 minutes ago, RFun said:

Of course, this map doesn't factor in that a backyard could conceivably have 3 different zones in it lol.  It's missing a lot of those detailed measurements in cold sink areas, up by buildings or near bodies of water, etc.

From the USDA Page https://planthardiness.ars.usda.gov/pages/how-to-use-the-maps

"

If your hardiness zone has changed in this edition of the USDA Plant Hardiness Zone Map (PHZM), it does not mean you should start removing plants from your garden or change what you are growing. What has thrived in your yard will most likely continue to thrive.

Hardiness zones in this map are based on the average annual extreme minimum temperature during a 30-year period in the past, not the lowest temperature that has ever occurred in the past or might occur in the future. Gardeners should keep that in mind when selecting plants, especially if they choose to "push" their hardiness zone by growing plants not rated for their zone. In addition, although this edition of the USDA PHZM is drawn in the most detailed scale (1/2 mile square) to date, there could still be microclimates that are too small to show up on the map.

Microclimates, which are fine-scale climate variations, can be small heat islands—such as those caused by blacktop and concrete—or cool spots (frost pockets) caused by small hills and valleys. Individual gardens also may have very localized microclimates. Your entire yard could be somewhat warmer or cooler than the surrounding area because it is sheltered or exposed. You also could have pockets within your garden that are warmer or cooler than the general zone for your area or for the rest of your yard, such as a sheltered area in front of a south-facing wall or a low spot where cold air pools first. No hardiness zone map can take the place of the detailed knowledge that gardeners learn about their own gardens through hands-on experience.

Many species of perennial plants gradually acquire cold hardiness in the fall when they experience shorter days and cooler temperatures. This hardiness is normally lost gradually in late winter as temperatures warm and days become longer. A bout of extremely cold weather early in the fall might injure plants even though the temperatures may not reach the average lowest temperature for your zone. Similarly, exceptionally warm weather in midwinter followed by a sharp change to seasonably cold weather may cause injury to plants as well. Such factors could not be taken into account in the USDA PHZM.

All PHZMs should serve as general guides. They are based on the average lowest temperatures, not the lowest ever. Growing plants at the extreme range of the coldest zone where they are adapted means that they could experience a year with a rare, extreme cold snap that lasts just a day or two, and plants that have thrived happily for several years could be lost. Gardeners need to keep that in mind and understand that past weather records cannot provide a guaranteed forecast for future variation in weather.

Other Factors Affecting Plant Survival

Many other environmental factors, in addition to hardiness zones, contribute to the success or failure of plants. Wind, soil type, soil moisture, humidity, pollution, snow, and winter sunshine can greatly affect the survival of plants. The way plants are placed in the landscape, how they are planted, and their size and health might also influence their survival.

•    Light: To thrive, plants need to be planted where they will receive the proper amount of light. For example, plants that require partial shade that are at the limits of hardiness in your area might be injured by too much sun during the winter because it might cause rapid changes in the plant’s internal temperature.

•    Soil moisture: Plants have different requirements for soil moisture, and this might vary seasonally. Plants that might otherwise be hardy in your zone might be injured if soil moisture is too dry in late autumn and they enter dormancy while suffering moisture stress.

•    Temperature: Plants grow best within a range of optimal temperatures, both cold and hot. That range may be wide for some varieties and species but narrow for others.

•    Duration of exposure to cold: Many plants that can survive a short period of exposure to cold may not tolerate longer periods of cold weather.

•    Humidity: High relative humidity limits cold damage by reducing moisture loss from leaves, branches, and buds. Cold injury can be more severe if the humidity is low, especially for evergreens."

[RFun]

11 minutes ago, Allen said:

From the USDA Page https://planthardiness.ars.usda.gov/pages/how-to-use-the-maps

"

If your hardiness zone has changed in this edition of the USDA Plant Hardiness Zone Map (PHZM), it does not mean you should start removing plants from your garden or change what you are growing. What has thrived in your yard will most likely continue to thrive.

Hardiness zones in this map are based on the average annual extreme minimum temperature during a 30-year period in the past, not the lowest temperature that has ever occurred in the past or might occur in the future. Gardeners should keep that in mind when selecting plants, especially if they choose to "push" their hardiness zone by growing plants not rated for their zone. In addition, although this edition of the USDA PHZM is drawn in the most detailed scale (1/2 mile square) to date, there could still be microclimates that are too small to show up on the map.

Microclimates, which are fine-scale climate variations, can be small heat islands—such as those caused by blacktop and concrete—or cool spots (frost pockets) caused by small hills and valleys. Individual gardens also may have very localized microclimates. Your entire yard could be somewhat warmer or cooler than the surrounding area because it is sheltered or exposed. You also could have pockets within your garden that are warmer or cooler than the general zone for your area or for the rest of your yard, such as a sheltered area in front of a south-facing wall or a low spot where cold air pools first. No hardiness zone map can take the place of the detailed knowledge that gardeners learn about their own gardens through hands-on experience.

Many species of perennial plants gradually acquire cold hardiness in the fall when they experience shorter days and cooler temperatures. This hardiness is normally lost gradually in late winter as temperatures warm and days become longer. A bout of extremely cold weather early in the fall might injure plants even though the temperatures may not reach the average lowest temperature for your zone. Similarly, exceptionally warm weather in midwinter followed by a sharp change to seasonably cold weather may cause injury to plants as well. Such factors could not be taken into account in the USDA PHZM.

All PHZMs should serve as general guides. They are based on the average lowest temperatures, not the lowest ever. Growing plants at the extreme range of the coldest zone where they are adapted means that they could experience a year with a rare, extreme cold snap that lasts just a day or two, and plants that have thrived happily for several years could be lost. Gardeners need to keep that in mind and understand that past weather records cannot provide a guaranteed forecast for future variation in weather.

Other Factors Affecting Plant Survival

Many other environmental factors, in addition to hardiness zones, contribute to the success or failure of plants. Wind, soil type, soil moisture, humidity, pollution, snow, and winter sunshine can greatly affect the survival of plants. The way plants are placed in the landscape, how they are planted, and their size and health might also influence their survival.

•    Light: To thrive, plants need to be planted where they will receive the proper amount of light. For example, plants that require partial shade that are at the limits of hardiness in your area might be injured by too much sun during the winter because it might cause rapid changes in the plant’s internal temperature.

•    Soil moisture: Plants have different requirements for soil moisture, and this might vary seasonally. Plants that might otherwise be hardy in your zone might be injured if soil moisture is too dry in late autumn and they enter dormancy while suffering moisture stress.

•    Temperature: Plants grow best within a range of optimal temperatures, both cold and hot. That range may be wide for some varieties and species but narrow for others.

•    Duration of exposure to cold: Many plants that can survive a short period of exposure to cold may not tolerate longer periods of cold weather.

•    Humidity: High relative humidity limits cold damage by reducing moisture loss from leaves, branches, and buds. Cold injury can be more severe if the humidity is low, especially for evergreens."

This is very important.  Lots of people get caught up in the maps and lose sight of this.

[fr8train]

This area is creeping up on 9a now yet some supposedly zone 8 palms burnt to a crisp and died as recently as last winter. From what I understand this map doesn't reflect the last few winters? 

[fr8train]

Does anyone know how they get the information in order to determine where the actual line between zones is, like below? 

Edited November 15, 2023 by fr8train

[RFun]

1 minute ago, fr8train said:

Does anyone know how they get the information in order to determine where the actual line between zones is, like below? 

No, but I'm sure you could drive through this entire area that is showing two zones and not even notice anything different lol.  The plants don't usually magically decide anything on the hardiness zone parameters of whether it's a 49 or 50 average lol.  If anything, it's likely the middle range of a given zone where the damage can be done.

[fr8train]

21 minutes ago, RFun said:

No, but I'm sure you could drive through this entire area that is showing two zones and not even notice anything different lol.  The plants don't usually magically decide anything on the hardiness zone parameters of whether it's a 49 or 50 average lol.  If anything, it's likely the middle range of a given zone where the damage can be done.

Right, this area is interesting though as the zone shifts in a very small area from 9a to 8a according to that map. 

Edited November 15, 2023 by fr8train

[RFun]

17 minutes ago, fr8train said:

Right, this area is interesting though as the zone shifts in a very small area from 9a to 8a according to that map. 

I see what you mean.  Looks like it goes from a very strong 8a (at the least) to the lower end of 9a.