Wind Chill Effect on Cold Hardiness?

[OriolesRock100]

Hello all, I was searching for an answer to this question, and I found mixed/unclear answers on the internet, with some sources saying wind chill does not matter, but some saying it would result in more damage. I thought I'd ask here - How does the "Feels Like" temperature/wind chill affect palm cold hardiness? I am aware that wind can damage fronds, but will it change whether or not a palm will survive or be damaged by a cold spell? It is spring here in Pennsylvania, and my palms that are in pots are being moved inside and outside as cold/warm fronts come in every couple days due to high variance in temperatures (as spring usually is around here). If a storm rolls through that not too cold but extremely windy such as now, I am trying to understand when I need to move the palms inside. For example, I have a potted trachycarpus fortunei that I usually bring inside once it gets into the mid 20s. Right now, the temperature is 45° with a "feels like" temperature of 25° due to 30+ mph wind gusts. The low overnight will be 33° actual temperature but "feels like" 14°. Should I bring them inside in this case? It would never have damage with 33° lows overnight normally, but the wind chill is quite low which worries me a bit. Would appreciate any insight on the topic of wind chill in cold hardiness for palms. Thanks!

[NC-Key-Bar]

The "Feels like" is just that.  What it feels like to a human on bare skin.  We create our own body heat.  So think of things like wind/water being a force that quickly removes the heat generated from our bodies.  I think the opposite is easiest to explain...

100 degrees in dry Las Vegas heat-> you sweat, and it quickly evaporates into the dry air - allowing you to cool "easily".  Ive walked around the Vegas strip at 100 degrees and not have sweat on my shirt.  Or a cold drink by the pool, and no condensation on it! weird.
Now, 90 degrees in Florida at 90% humidity - The air is saturated already, making that water harder to evaporate away - slowing down how well you can cool yourself.  And you're drenched in sweat almost immediately.
This is where the humidity impacts the "feels like" temp.

This is how I understand it.

[SailorBold]

It's effect on cold hardiness is prolly next to zero.. as far as damage goes it may be more of a factor because at cooler air/soil temps the plant systems water uptake..circulation per se..is alot slower than during the growing season.. the leaves will transpire the water more quickly and possibly the leaves will desicate because it can't replace the moisture loss.. now thinking about that..it may have an effect on the palms survival but not necessarily it's overall cold hardiness.. not sure if spear pull is a factor in all that versus freezing in the bud..

[jwitt]

A 40f air temperature with a thirty mph wind creates a 28f  windchill. A palm totally exposed to these conditions is 40f, not 28f.

In other terms, if windchill was a factor, coconut palms would not exist in south Florida. 

[OriolesRock100]

Thanks for the responses guys. So the conclusion I've derived from your answers is that I should only look at the actual temp regardless of the wind when it comes to strictly palm survival of cold. If I'm worried about potential frond damage, it could be something to consider because of increased transpiration. Sounds like what this means for me is that maybe I should move some of the slower-growing palms like sabals inside during this windy/cold event to avoid setting them back too much for the growing season.

[puddingnpie]

I'm a bit skeptical here. Doesn't cold wind pull away heat from the palm?

[jwitt]

4 hours ago, puddingnpie said:

I'm a bit skeptical here. Doesn't cold wind pull away heat from the palm?

Not sure how to make this anymore clear.

Drive your car down the road at 60 mph in a 35f temperature for an hour.  What temperature do you think the windshield would be?  I am going to say 35f or more, although the windchill is 17f. 

I guarantee a sealed jug of water on  the roof of the car won't freeze in those conditions. 

Or to the extreme, a palm sitting in 500mph winds at 35f is going to be 35f........if a palm could sit in those winds.  Substitute a metal pole, gonna be the air temp, not the windchill temperature. 

The palm in your example becomes the air temperature, not the windchill temperature.  

The temperature  on your dash readout would drop everytime you increase speed.  It doesn't. 

Yes, increased wind will make the palm closer to the air temperature, irregardless if the air is cold or hot. 

 

[LeonardHolmes]

I think that wind does affect palms, but differently than it affects skin.  Plant one marginal palm in a really windy open spot and another in a spot sheltered from the wind - and I'd bet that the sheltered palm does better all other factors being equal.  It's not the "wind chill" value that affected the windy palm - it's the exposure to the wind over time.

[ahosey01]

19 hours ago, jwitt said:

A 40f air temperature with a thirty mph wind creates a 28f  windchill. A palm totally exposed to these conditions is 40f, not 28f.

In other terms, if windchill was a factor, coconut palms would not exist in south Florida. 

But then how does this account for the fact that in big windy freeze events it is always the north side of the woody trees that is damaged?

[jwitt]

57 minutes ago, ahosey01 said:

But then how does this account for the fact that in big windy freeze events it is always the north side of the woody trees that is damaged?

Increased heat transfer(loss). Not windchill. 

Same as no canopy damage on a radiatonal night(upper leaf damage). Also not wind chill.  Just increased heat transfer. 

RGV is a great example showing that plants growing in the area would never survive if plants actually felt windchill. RGV see's incredibly low wind chills, every year. 

[CascadiaPalms]

A video I made a few months ago...it's not perfect, but it gets to the basics and to the point.

 

[Swolte]

@NC-Key-Bar is correct but I do think its only part of the story. In my experience/understanding wind chill can certainly increase cold damage although through different, indirect mechanism. Especially if part of the soil is frozen, roots lose the ability to absorb water efficiently. High (especially dry) winds can cause plants to lose moisture faster, which, added to frozen ground, can expedite dehydration leading to foliar damage.

EDIT: Had not watched the video but I guess it makes a similar point more elegantly.
:p

[jwitt]

@CascadiaPalms palms do produce heat.  All matter does. 

Cold is only a theory. Or better stated, "there is no such thing as cold, only the absence of heat".

Absolute zero(absence of heat/energy) is only a theory. 

I liked your video!

 

[Fusca]

I agree with comments regarding wind chill.  But that's not to say that wind doesn't affect the cold event and plant damage.  An advective freeze (most common type in most of Texas) is accompanied by strong winds and a sudden drop in temperature and is very different than a radiation freeze which is heat radiating away from the ground on a clear night with the coldest temperature at the ground surface.  Wind or lack of it can determine duration of freezing temperatures and whether juvenile palms are more at risk.

[CascadiaPalms]

31 minutes ago, jwitt said:

@CascadiaPalms palms do produce heat.  All matter does. 

Cold is only a theory. Or better stated, "there is no such thing as cold, only the absence of heat".

Absolute zero(absence of heat/energy) is only a theory. 

I liked your video!

 

Thank you.

....and yes, that is true about matter, you are right.  And I've heard that theory.  I think I look at it kind of in a way like a cold-blooded animal, but in a plant sense in their world under their rules.  At the end of the day, plants can't regulate their temperature which means they are highly influenced by the ambient temperature and factors in their environment.  

[ahosey01]

1 hour ago, Fusca said:

I agree with comments regarding wind chill.  But that's not to say that wind doesn't affect the cold event and plant damage.  An advective freeze (most common type in most of Texas) is accompanied by strong winds and a sudden drop in temperature and is very different than a radiation freeze which is heat radiating away from the ground on a clear night with the coldest temperature at the ground surface.  Wind or lack of it can determine duration of freezing temperatures and whether juvenile palms are more at risk.

Yeah the way I understand it... windy freeze = no microclimates anywhere, still freeze = lots of microclimates.

11 hours ago, jwitt said:

Increased heat transfer(loss). Not windchill. 

Same as no canopy damage on a radiatonal night(upper leaf damage). Also not wind chill.  Just increased heat transfer. 

RGV is a great example showing that plants growing in the area would never survive if plants actually felt windchill. RGV see's incredibly low wind chills, every year. 

I'm not that smart so help me make sure I've got it.

To use your windshield example, if greater wind speed = greater heat transfer, I think what you're saying is something like this:

• Pull a car out of your garage (50F) and drive it around in 30F temps at 30mph, it will take X minutes to drop from 50F-30F.
• Pull that same car out of the garage and drive it around in the same temps at 100mph, anad it will take X minus Y minutes to drop from 50F to 30F, with Y representing the increased heat transfer caused by increased wind speed.

Is that right?

[JLM]

Only way a wind chill could affect a palm is if you’re providing heat for protection and do not put enough layers over that to hold that heat in properly, and even then that’s literally just wind. Otherwise as mentioned above, it’ll be whatever the real temperature is. Wind chill and heat index, or feels like, is exactly what it says. That’s the temperature it feels like to humans and animals, a tree cannot feel the feels like temperature.

Saw mentions of microclimates. Advective freezes are gonna significantly reduce or remove microclimate effects depending on how strong the wind is. Microclimates thrive on radiational nights where no wind is present. Soil conditions, local elevation, moisture can all impact how cold it gets and where. You can have 34F at your house, and then down the road a few houses down it can be 29F. A weather station a mile away from your house may not be an accurate representation of your actual temperature.

[jwitt]

4 hours ago, ahosey01 said:

use your windshield example, if greater wind speed = greater heat transfer, I think what you're saying is something like this:

• Pull a car out of your garage (50F) and drive it around in 30F temps at 30mph, it will take X minutes to drop from 50F-30F.
• Pull that same car out of the garage and drive it around in the same temps at 100mph, anad it will take X minus Y minutes to drop from 50F to 30F, with Y representing the increased heat transfer caused by increased wind speed.

Is that right?

@ahosey01 I was pointing out that the windshield would be the ambient temperature(or above) and not the windchill temperature. 

Or stick your bare arm out the window going highway speeds, and your arm will sense the windchill. The same condition a thermometer will read the ambient temperature, not windchill. 

Your examples demonstrate the increased heat transfer and are correct. 

If windchill were a thing, your windshield would ice going down the highway in 40f weather,........... everytime. 

 

 

[jwitt]

16 hours ago, LeonardHolmes said:

I think that wind does affect palms, but differently than it affects skin.  Plant one marginal palm in a really windy open spot and another in a spot sheltered from the wind - and I'd bet that the sheltered palm does better all other factors being equal.  It's not the "wind chill" value that affected the windy palm - it's the exposure to the wind over time.

Great example of radiationial vs. abjective freeze.  Abjective having greater heat transfer(loss) and more damaging. 

[LeonardHolmes]

11 hours ago, Fusca said:

 An advective freeze (most common type in most of Texas) is accompanied by strong winds and a sudden drop in temperature and is very different than a radiation freeze which is heat radiating away from the ground on a clear night with the coldest temperature at the ground surface. 

Great explanation. I also learned a new vocabulary word in the process.  

[Yort]

 A plant is quite different to a car window. A plant leaf can have transpirational cooling. It transpires water vapor creating a moist air layer surounding the leaves. (Dry) wind will remove this vapor more quickly causing increased rates of transpiration. (Hardy) palms dehydrate their cells in preparation of frost. They do this to lower the freezing point of water in their cells. Wind will increase dehydration acceletating the waterloss. When dehydration is at a certain level or a palm is dehydrated to long the meristemic cells in the apical bud will be damaged and result in what we call spear pull. In addition to this wind may also cause mechanical damage to frozen plant tissue.

[jwitt]

8 hours ago, Yort said:

 A plant is quite different to a car window. A plant leaf can have transpirational cooling. It transpires water vapor creating a moist air layer surounding the leaves. (Dry) wind will remove this vapor more quickly causing increased rates of transpiration. (Hardy) palms dehydrate their cells in preparation of frost. They do this to lower the freezing point of water in their cells. Wind will increase dehydration acceletating the waterloss. When dehydration is at a certain level or a palm is dehydrated to long the meristemic cells in the apical bud will be damaged and result in what we call spear pull. In addition to this wind may also cause mechanical damage to frozen plant tissue.

So palms in a colder, windy(z7-8) desert climate should have higher spear pull rate than a wetter, less windy (z7-8) climate?

[ahosey01]

On 3/8/2025 at 2:21 AM, jwitt said:

Great example of radiationial vs. abjective freeze.  Abjective having greater heat transfer(loss) and more damaging. 

I think this is advective.  Abjective is like demoralizing or shameful.

[Yort]

48 minutes ago, jwitt said:

So palms in a colder, windy(z7-8) desert climate should have higher spear pull rate than a wetter, less windy (z7-8) climate?

No, because a palm growing in a drier area will already be adapted to that environment. Leaf morphology will be different, smaller leaves, less green leaves in the crown, lower stomatal count per area etc.

[Jeff zone 8 N.C.]

Two things to consider that I have questions about is that at least in my area the ground is much warmer than the air. Our ground, even at shallow depths, remains 65F constantly, year round, so our ground gives off heat to the cold winter air. The ground here very,  very rarely freezes at all and if so it is only a short lived very shallow crust. This would mean "still air" would tend to help a plant, at ground level, stay warmer versus a wind that would mix the air near the ground. So would that not be an advantage? Also the time that air stays on a surface (like a Leaf) is called "Dwell time". If cold air dwells or stays on a surface, like a leaf, longer then it exchanges temps less efficiently with that leaf so the temp of that leaf may stay a little warmer but as wind blows then the temp exchange is constantly being refreshed with new colder air. Another thing to consider is overhead canopy.  We all know that helps in a freeze. If trees are overhead then it would help to trap warmer ground air near the plant. Just saying that different conditions need different considerations. Not trying to debate anyone here just hoping that this can be explained in context with what has been posted so far.

[jwitt]

1 hour ago, Yort said:

No, because a palm growing in a drier area will already be adapted to that environment. Leaf morphology will be different, smaller leaves, less green leaves in the crown, lower stomatal count per area etc.

Great information!

But until that happens ( 1-3 growing seasons) a newly planted palm(in a desert/dry) would have a higher rate of spear pull than one in a similar wetter zone using your hypothesis. 

Is that correct?