Up to 80% of UV Gets Through Clouds — Yes, You Still Burn
Gray skies feel like a sunscreen day off, but up to 80% of UV slips through cloud cover — so the burn and the DNA damage still happen.
According to the Skin Cancer Foundation, as much as 80% of UV rays pass through cloud cover, so sunburn and DNA damage happen on overcast days; thin clouds can even scatter and slightly increase UV exposure at the edges.
The Skin Cancer Foundation stresses that because the sun's warmth and brightness are what usually cue people to seek shade, cloudy days are deceptively risky — the UV is still arriving even when it doesn't feel like it.
Questions we get a lot
Can you really get sunburned on a cloudy day?
Yes. The Skin Cancer Foundation notes that as much as 80% of UV rays pass through cloud cover, so sunburn and DNA damage still occur on overcast days. Thin clouds can even scatter UV and slightly raise exposure. The lack of heat and glare just makes the risk easier to ignore.
Should I wear sunscreen when it's overcast?
Yes — because clouds block only a fraction of UV, daily broad-spectrum sunscreen is still worthwhile when it's gray out. The Skin Cancer Foundation points out that UV damage accumulates regardless of how the sky looks. Treating sunscreen as a daily habit, not a sunny-day add-on, is the safer approach.
r/SkincareAddiction: 'It's been overcast for a week straight where I live — am I actually wasting product putting on SPF every morning, or does cloud cover not help?'