27

Yes it is possible to sunburn through clothing. Clothing does block some of the Ultraviloet radiation but not 100%. A lot of outdoor recreation clothing is now marketed with treatments that gives additional UV protection.


24

It's because the sunlight will damage the tents fabric over time. UV damage occurs when long term exposure to the sun damages the fabric and thread of your tent or rain fly. The fabric will become thin and brittle. If you tent or rain fly seems to rip for no reason or with very light pressure, this could be the reason. The outside of the fabric will often ...


22

A tent's UV resistance isn't for you, it's for the tent. High-energy UV rays will break down many synthetic and natural textiles over time. UV resistant fabrics are not as susceptible to this breakdown, and will last longer with repeated exposure to sunlight. UV resistant fabrics are great if you're looking for long-lasting gear that will be used in ...


16

All sunscreens are physical barriers, designed to absorb or reflect UV radiation. They rub off over time, and they will rub off faster when exposed to water/moisture, most commonly from sweating or swimming. Friction (e.g. from towel-drying) also removes sunscreen. Some chemical sunscreens do break down when exposed to sunlight and require the addition of ...


16

As it is stated in this Wikipedia article, the sun protection factor (SPF) roughly describes how the time that your skin is able to protect itself from sunburn is elongated. To take the Wikipedia example: if a person develops a sunburn in 10 minutes when not wearing a sunblock, the same person will prevent sunburn for 150 minutes if he/she wears a ...


15

Around sunrise and sunset, the sun is much less intense. You would get around 5 times less intensity in the first or last hour of sunlight than in the middle of the day. Here is a graph of this effect (It's from a paper, though the paper itself is behind a paywall), graph http://ars.sciencedirect.com/content/image/1-s2.0-S0960148108003091-gr4.jpg and ...


13

The wikipedia article on sun protective clothing is very informative. A summary of the relevant parts: Apart from clothing specifically marketed as protecting against the sun most clothing will not block all sun to fully protect you against sunburn depending on circumstances. Some general rules of thumb: Darker clothes provide more protection than lighter ...


13

As found here: "With every 1000 m in altitude, UV levels increase by approximately 10 per cent." Percentages are tricky to work with, so here is a worked-out example. Suppose you start out at sea level (0m), and you climb all the way up to Mt. Everest's summit (8848m). Suppose also that at sealevel, you normally need to apply sun block factor 15. Then, ...


12

Polarized sunglasses, as with other type of sunglasses may not block enough UV to be considered safe. From WikiPedia: for adequate protection, experts recommend sunglasses that reflect or filter out 99-100% of UVA and UVB light, with wavelengths up to 400 nm. Sunglasses which meet this requirement are often labeled as "UV400. In other words, you ...


12

@fygsin has this more or less correct, but to expand on the answer: This is long so TL:DR - In vitro = in glass - lab based measurements, not performed using real sunlight. Higher number = better protection. Tests measure absorbance of UV by the chemicals, not reflection. UV is classified into 3 types of rays based on wavelength. Each subtype has, in ...


11

I'd like to add to the existing answer that while sunscreen effectiveness does decrease as it is absorbed into the body, wears off, or is washed off, high SPF sunscreens will still block most sun after the two hours. The FDA recommendations for reapplication every two hours are basically to provide maximum protection, because the level of protection does ...


11

Polarization and UV protection on sunglasses are two different things. While UV refers to light of a wavelength of approximately 10nm to 400nm, light of any wavelength can be polarized. Sunglasses with a polarization filter block light, that is horizontally polarized (e.g. light reflected on water). This has no specific effect on UV-light. So polarized ...


11

You will want to look for a sun cream that is designed for swimming - don't bother looking for specific ingredients, look for the bottles that say they are for sun and swim. Usually in addition to the SPF they will have a rating or guide as to how often you need to reapply (eg every swim, or every two swims) @ShemSeger's comment is the recommended way to ...


11

In Europe your will be hiking on altitudes less than 5000 m, and on these altitudes you can go with sunglasses without heavy specialized equipement. However not any piece of sunglasses will do. First, they have to be either made of glass (which stops UV rays) or special UV-proof plastic. Not every plastic stops UV rays, and if not, using it is even more ...


11

When I first planned my trek in Himalays I was suggested to keep my Gogs and Glares with me when I am outdoor-bound, in snow. A good article in my Adventure related Database rtf files says: Hours of bright sunlight can burn the surface of the eye, causing a temporary but painful condition known as Photokeratitis. Over time, unprotected exposure can ...


11

Use your finger. Equally to using your finger to cover the sun when trying to spot something in the sky you can use the principle to cover the bright spot. You will be closing one eye and putting the finger between your eye and the bright spot to cover it just enough to not bother you I used that system several times both with the sun but also if I had ...


8

Heat illnesses are about heat, not light, and while the two are not unrelated, the hue of your clothing would be a very minor factor— red would not provide better or worse protection than green or blue or any other part of the visible spectrum. The shade may have some impact: since darker clothing absorbs more energy than lighter clothing, it warms up and ...


8

One of the classic applications of polarized sunglasses is to skiing. Light from the sun is unpolarized, but when it is reflected from a surface at a glancing angle, it becomes highly polarized. When you're on a snow field, a lot of the bright light getting into your eyes is light reflected from the snow, and when the sun is low in the sky, this glare is ...


8

Those types of glasses do not provide adequate protection from sunlight, especially in areas with lots of reflective surfaces (desert, snow) and at high elevations where there's more UV radiation due to the thinner atmosphere above you. What you want are either wrap-around glasses which don't let light in the sides, or particular glasses called "glacier ...


8

I would just use eclipse glasses. As they are safe to look directly at the sun with, then they should be fine to look at the bright spot caused by the magnifying glass. Just make certain that they are certified and not rip-offs and then you should be good to go. They meet all of your requirements and would be no more trouble to take with you than a pair of ...


7

These are generally known as glacier glasses. They are rated as Category 4 on the CE scale and you aren't supposed to drive while wearing them. Sunglasses in Category 4 only transmit 4-8% of available visible light. Hidalogos sunglass guide has a very complete list of the different factors in choosing sunglasses. Category 4 come in a wider range of ...


7

I really like the existing answer, but I feel like it is a bit misleading in regards to what SPF really means. Reading that quote makes it seem like SPF is a linear relationship between SPF and the time before you will get burned. That isn't strictly true. A more extended quote from Wikipedia is (emphasis mine): The sun protection factor (SPF rating, ...


7

Sounds like what you're looking for is either an undersuit, or simply some swimming pants/tights. Wetsuit undersuits are worn under diving wetsuits to add insulation and comfort to the suit, and they help slide the suit on and off a bit easier, some are essentially built like a body-rashguard. Swim tights are exactly what they sound like, tight pants that ...


7

It's interesting but just banging amazon with "linen shirt upf" didn't do anything good. But it turned up another subpage of your referenced page. It has a nice graphic with a distribution of UPF Rating per material, which should give you a rough direction of how big the differences per material are actually. Which gives a general direction. From what I ...


7

Good snow goggles as described in ab2's answer take a while to make. A quick and dirty way for temporary use can be made with bark. Birch bark is probably easiest to work with, but any smooth bark that you can peel off the tree should work. Try alder and aspen, and willow. You may need to make a baton and pound on the tree some to loosen the bark. Don't ...


6

According to this health-related website, you should still wear a shirt: You should not think of sunscreen as an alternative to avoiding the sun or covering up. It is used in addition. Sunscreens should not be used to allow you to remain in the sun for longer - use them only to give yourself greater protection. No sunscreen is 100% effective and so it ...


6

Your mileage may vary, so know thyself. Start conservative, it is easier to back-off on protection than it is to treat sunburns. SPF 50 is not too high and you may want an even higher SPF when starting. Sunscreen that contains titanium dioxide or zinc oxide is great because they protect against both UVA and UVB. Since they are also inorganic compounds ...


6

I own only glacier glasses and use them as sunglasses as well (I take off the "blinders"). If you decide to go with sunglasses only, make sure they offer proper UV protection (not all of them do). Reasons as explained by @WedaPashi (I'd only add that while cataracts can be operated IMHO that is no reason not to try and avoid them).


6

This article has a list of what chemicals to avoid, why, and some good sunscreen choices. The three main points are below. Note that titanium dioxide falls under physical sunscreen but is still harmful! So saying physical is okay but chemical ones are not is FALSE. I personally have used Raw Elements and Stream2Sea before and been pretty happy with them. ...


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