The IceRays field guide
The wet test: what wetting a cooling sleeve really shows
You may have seen the "wet test": someone splashes water on a cooling sleeve, pulls it on and says how cold it feels. It is a fun thing to try. But it is easy to read more into it than it shows. Here is what the wet test really tells you, and what it does not.
What happens when you wet a sleeve
Damp fabric feels cool as the water dries off it. A breeze, or you walking along, speeds that up. It is the same reason a wet swimming costume feels chilly on a windy beach. Nothing special or secret is going on. It is plain evaporation.
Thin, stretchy fabric spreads water out over a wide area, so it can dry fast. That is why a damp sleeve can give a quick, noticeable chill. On a still, humid day it dries slowly, so the feeling is weaker. On a dry, breezy day it is stronger.
What the wet test shows
- That damp fabric feels cool on the skin while it dries.
- That the sleeve is thin and light enough to dry out quickly.
- That the fit is snug enough to stay in place when damp.
What the wet test does not show
- It is not a temperature measurement. How cool it feels is your sensation, not a reading. We make no claim about a set drop in skin temperature.
- It is not a sun protection test. Feeling cool tells you nothing about how much UV the fabric blocks.
- It does not last all day. Once the water dries, the extra chill goes with it.
- It does not make a hot day safe. Water, shade and rest still matter most.
The catch: wet fabric blocks less UV
This is the bit most wet-test videos leave out. Cancer Council says fabrics offer less protection from UV when wet. How much less depends on the fabric and how much water it holds.
UPF is a rating for fabric. UPF 50+ means the fabric blocks 98% or more of UV. Those ratings are measured on dry fabric that is not stretched. IceRays fabric was tested by ARPANSA in 2015 (black sample) and rated UPF 50+. That test was on a dry sample. It does not tell us how much protection a soaked sleeve gives. You can read what the 2015 test covered (PDF, opens in a new tab) for yourself.
So here is our plain advice. If you are going to be out in strong sun for a long time, wear your sleeves dry for sun cover. Let sweat do the cooling as you go. If you do dampen them for comfort, know that you are trading some sun protection for that chill.
Our archival cooling video
In 2018, an IceRays video showed a handheld infrared thermometer pointed first at a bare forearm, and then at the outside of a sleeve, in the same spot. We keep it as an archival demonstration. Please read it for what it is:
- It reads the outer surface of the fabric, not the skin under the sleeve.
- It was one setting, on one day, not a controlled experiment.
- It is not a wet-versus-dry protection test.
We do not quote its readings as a promise of how cool you will be. If we ever run a proper, measured test, we will publish the method alongside the results.
Trying it yourself, safely
If you want to feel the effect, here is a sensible way to do it.
- Do it before you set off, not on the move. Never dampen or adjust sleeves while driving, riding a bike or using tools.
- Use clean tap water. A light dampening is plenty; you do not need them dripping.
- Pull the sleeves on and notice the feeling as you walk around in the breeze.
- When they dry out, compare. You may find sweat alone keeps you comfortable enough.
When you wash your sleeves, follow the care label. That is the best guide for keeping the fabric in good shape.
What really keeps you comfortable in the heat
The wet test is a party trick next to the basics. On a hot day:
- Plan outdoor time for the cooler part of the day where you can.
- Drink water before you feel thirsty, and take breaks in the shade.
- Wear a broad-brimmed hat and put sunscreen on skin your clothes do not cover.
- Know the warning signs of heat illness. healthdirect has a clear guide to heatstroke, what to do and how to avoid it.
Light arm sleeves can be part of that routine. They are one helpful layer, not the whole answer.
Keep reading
- Do cooling sleeves work? An honest answer
- Golf in the heat over 60
- Gardening in the sun: how to cover up without overheating
- How to care for sun sleeves
- UPF vs SPF explained
The IceRays 4-pack is AUD 120 for four pairs, or $30 a pair. That saves $31.80 on four single pairs. One size fits all adults.
Related guides
- Fishing sun sleeves: keep arm cover in your tackle routine
- Sun sleeves for kayaking: arm cover on the water, and the facts about wet fabric
- UV arm sleeves: the complete guide
Common questions
Do I need to wet my sleeves for them to work?
No. Sleeves cover your arms whether they are wet or dry. Sweat and a breeze give most of the cool feeling. Dampening them is optional, and wet fabric blocks less UV.
How long does the cool feeling last after wetting?
Only until the fabric dries. On a dry, breezy day that can be quick. On a humid day it lasts longer but feels weaker.
Is a wet sleeve still UPF 50+?
We cannot say. The 2015 test was on dry fabric, and Cancer Council says fabrics give less protection when wet. Wear them dry when you want the most sun cover.
Can I use salt water or pool water?
We suggest clean tap water. For washing afterwards, follow the care label on your sleeves.
Does the thermometer video prove the sleeves cool my skin?
No. It reads the outside of the fabric, not the skin underneath, on one day in one setting. We show it as an old demonstration, not as proof.