On the bike, I'm cooler in hot weather wearing skin-tight everything. We're water-cooled beings when it's hot, and water evaporates most quickly when it's exposed to moving air, hence tight, thin, wicking clothing. That said, my experience is in climates with humidity mostly under 70% in summer. It's my impression that stark white sunsleeves don't diminish the rate of sweat evaporation, plus being white means they don't absorb heat as much as your skin of whatever color. I don't like hot climbs with a tailwind, when the sweat off your nose lands on your top tube.

Tight clothing certainly does keep airflow off your pores. It's okay in the desert. The first time I rode through Death Valley, I wore black, fleece-lined leg warmers (all I had with me) even though it was 120 on the tarmac, they didn't get wet from sweat. There is no experience of sweating out there it's so dry. And I have heard the advice to wear tight clothing in the desert because it does slow evaporation and will keep you from getting dehydrated too quickly.

When i went back, I followed the lead of folks who have lived in the desert for centuries; fully covered, lose-fitting, light colored. Very comfy. Like wearing shelter. ,

Back home in hot, humid New England, I would want as little against my skin as possible. In my experience, lycra is not the same as bare skin; it does hinder water transfer from skin to air. Less clothes is always better at 90 degrees and 90 percent humidity. Again, if you look at the people native to the east coast, they kept a lot of skin exposed.

https://cimg4.ibsrv.net/gimg/bikefor...8999462e5e.jpg

Loose clothing is fine for walking. Tight, wicking clothing is cooler for cycling. Even naked is not better for sweat cooling as has been proven by white sunsleeves. I've done long pass climbs in 105° full sun. Tight clothing works fine and doesn't flap. The airflow is not on your pores, it's on the surface of the wicking garment, where it evaporates quickly in the airflow. The problem with loose clothing is that the airflow is not on your pores and the sweat has not transferred to the surface of the garment where it could evaporate. Besides it's noisy and generates wind resistance, slows you down. There's no upside for cycling there.

Proven? I would love to read a study that proves any garment provides more cooling than bare skin.

Got a link?

Not more cooling. As I mentioned earlier, white sunsleeves, particularly PI (really, really white) reflect more sun than does naked skin. White garments make a big difference. To see how big, put a white and some event jersey like so many cyclists wear, out in the direct sun for a while, then feel them. Even yellow is hotter. One can feel the differences in a printed pattern.

As L. Francis Herreshoff said, "There are only two colors to paint a boat, white and black, and only a fool would paint one black." For the above reason.

Yeah, solar heating is a thing. As are evaporative cooling and convective heat transfer.

Taking all 3 factors into account, I still doubt that any garment is cooler than bare skin. I’m willing to be convinced otherwise by evidence. Got a link to some?

You're welcome to go hunting! I'm happy with my experience with them. The only thing I don't like is that can't tell if my forearms are staying wet. Dry forearms are my "you are about to have a health emergency" warning. I can't see droplets with sunsleeves on, though of course I could push them down for a few minutes if I were concerned.

From someone who knows:
I rode in 95f 95% heat for YEARS, and wore long sleeve shirts.
1. Darker colors protect better but are slightly warmer.
2. Long sleeves protect much better than sun screen. In extreme cases (you are REALLY sensitive AND out all day at the equator) use both
2a. Sunscreens protect a lot in some spectrums and less in others but rarely in all of the harmful spectrum and never over long term. Some sun screens can have long term effects on you and the environment long after you wash it away.
3. When wearing long sleeve wicking material in 95/95 weather, the first 5-10 minutes WILL feel really hot until you sweat, even in VERY humidity climates.
4. Tighter fit helps with cooling. Looser clothing creates an air pocket that will trap heat.
5. I've noticed that wicking material works better with no hair underneath, the hair, if thick enough, causes an air gap.
6. in dry and sometimes wet conditions, and your sweat is dripping off of you: that is useless sweat. Unless it evaporates, it does nothing to cool you. The increased surface area of the material allows for more efficient evaporation.

TL;DR
You pale?
Cover up.
Sunscreen if you can't

Or pay the price down the road

No study to reference, but my own experience in the desert southwest is that tight fitting anything (sun sleeves included) is cooler for cycling Definitely best to be bright white. Without sun sleeves, my experience is sweat simply runs down my arms. This provides little to no cooling when it just drips off. With the sleeves, the sweat gets spread out and evaporates. The evaporation is what causes the cooling. Having the evaporation happen from your skin or a fabric tight to your skin seems to work best. Having evaporation at the surface of loose clothing isn't going to do too much. Though if the clothing is a very loose weave, then potentially the air passing through would get cooled. Essentially like an evaporative (swamp) cooler. But only if this air reaches your skin.

While I can't say it works worse than bare skin, when I'm grinding uphill with a tailwind and have a nearly zero relative airspeed, the sleeves do seem warm. I think because at that point, they are just a layer of insulation and without any breeze, there's not nearly as much evaporation.

I get how loose clothing is a bit like wearing your own sun shade. And I think there's no question that for day-to-day living in the desert it works best. Else, why would desert nomads and similar have worn that for centuries. This is why when I do yard work I wear a hat with a huge brim, and very loose fitting sun shirt. Almost no bare skin.

I do not think loose clothing provides the best cooling when cycling and obviously loose clothing has drawbacks for cycling.

Many thousands of cyclists have settled on tight fitting clothing, thousands of desert peoples use lose fitting clothing. Horses for courses.

OK, I looked, found nothing. I should mention that I think they are not good for walking or standing around in terms of cooling. I push them down in rest stops, definitely hotter as they slightly insulate. But on the bike, the air movement seems to me to be cooler than my bare arms, which are not heavily tanned as I wear them in the sun and on hikes am often in tree shade or mountain shadow. I once tried wearing a bike jersey on a hike, total bummer, way too hot. A light, loose poly tee is best for my hiking, though I prefer a tight jersey on the bike. I've talked to many PCT thru-hikers and they're universally in the loose garment and lots of sunscreen camp. I'm not a fast climber, but I still seem to come out on the positive side, cycling with sunsleeves, even down to 7 mph as long as I don't have a tailwind.

I live in a tropical environment. Most of my cycling is early AM stuff. Although, group rides always extend past noon, so I wear sun sleeves. I highly recommend Pearl Izumi sun sleeves. I wear white. The fit is perfect and definitely worth the additional price tag compared with others. I have used the stretchy cheap ones and didn’t care for them at all.

Yup, I wear the long sleeve tops even in the real hot weather. Better than putting the sun screen goo on. This is after skin cancer on the face.

I wear sleeves nearly all the time. I find them fairly effective but not perfect at blocking sunlight, slightly better than a high SPF waterproof sun protection lotion. I do not find them hot. They do provide the ability to wick.
For context, I live in Toronto Canada. I do my best to avoid riding in weather hotter than approximately 28C.

Voler used to have some black sunsleeves. I guess nobody believed they wouldn't be hot, so they only have ugly ones now. I wish I had gotten the matching leggings when they were available. Maybe the white ones would be better in extreme temperatures, but the black ones have worked for me up to 95F. Taking them off didn't help, so the sun gain must be about the same as with bare skin. The advantage of sun sleeves in temperatures like that is that you can put ice in them.

Fortunately I live in a place where temperatures like that are rare.

I just thought I'd update this.

I had my surgery yesterday morning to remove the tumor. I was given a choice of procedures - one involved cutting out the area and a bit around it, stitches, a biopsy of the removed bits to make certain it was all removed, and a 2-3 week healing process, after which the stitches would have to be removed.

Option #2 was some long, convoluted medical terminology, which to me sounded like "something something something destruction." They use a heated wire 'scalpel" and remove the affected area by burning/scraping it down. It's good, because the wound is cauterized as they cut, so there is no bleeding. Also, no stitches. Recovery time is a bit longer (6-8 weeks) but there is no need to biopsy anything.

They had me at "destruction"! :)

The whole procedure took about 5 minutes from start to finish. Never felt a thing (good numbing job.) Once the numbing shots wore off, there was a little bit of discomfort, but even that went away later that evening. I changed out the bandage as told before bedtime. It doesn't look bad at all.

No tattoos were injured during the procedure. :D

I'm ordering new, custom, summer weight, long sleeve jerseys as well.
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I'm getting the skin chemo cream treatment.
Hoping to avoid the soldering iron scalpel treatment in the future.

Sometimes they can use liquid nitrogen to freeze the cancer cells and kill them.
The soldering iron scalpel really isn't that bad. It's healing up nicely, and there is zero pain. Yeah, there will probably be a scar, but.... chicks dig scars. :lol:

I've worn Elevengear Ginger long sleeve jerseys for seems like 10 years now. I own several of them so I don't have to wash every day. They are full zip which on the hottest days I leave unzipped. My riding position is aggressive so direct sunlight does not hit my chest area, ever. Kind of like riding under a shade tarp. Not saying you should get the jersey but if sleeves were made of similar materials I think you would like them.

New Orleans - South Louisiana. We often get "double hundreds" - 100°F and 100% humidity.

The higher the SPF factor, the tighter the weave = hotter. Generally speaking.

White reflects sunlight and does not absorb it very well. So white will be cooler to the touch but must have tighter weaves to achieve high SPF values.

With the exception of Patagonia "A/C" shirts, which are not cycling specific, I have not owned anything "cooler" than the Elevengear Ginger long sleeve jersey. Perhaps they are considering sleeves made from this material? Maybe contact them about it. Nice people.

https://cimg7.ibsrv.net/gimg/bikefor...bc134270c0.jpg

Some time ago, I did a deep dive on sunscreens and how much they really prevented skin damage and skin cancer. That dive had me concluding that when I choose to use sunscreen, I should avoid chemical sunscreens and stick with the sunblocks. They are a PITA to apply (sticky) and aren't easily washed off, but I think they are the safest alternative.

I typically do not wear any sunscreen on morning rides, as I am usually home by 10:30 and the uV exposure is low. I do wear sunscreen on longer rides and when I'll be out in the afternoon.

I rather like sunsleeves. I have Garneau sunsleeves and they're effective at at least reducing exposure to the sun. They're quite light and easy to carry, and are effective as "light" arm warmers. A good thing to have in any cyclist's riding attire, and especially so if you are prone to skin cancer.

Oh, and get yourself examined every year. Skin cancer, particularly melanoma, can appear in the strangest places.

Done the nitro gun a few times. Staying way ahead of this stuff. I've seen the alternative, and it's.... bad.

I always wear either a summer long sleeve jersey or a short sleeve summer jersey with arm sleeves. For arm sleeves, I first had Pearl Izumi ones. They were fine.

but I didn’t know what I was missing until I got nicer arm sleeves. I have Assos sleeves where every time I wear them, I think, “this is high quality stuff”

I also got some Rapha pro team sleeves that are also very nice.