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Seasonal / UV-Index Topics

Heatwave Skincare: Protecting Skin When It's Brutal Out

Extreme heat changes how you protect and recover.

By the numbers

Up to 80% of UV rays pass through clouds, so a hazy, sweltering heatwave day still delivers burning levels of UV (Skin Cancer Foundation).

Dermatologists stress that staying hydrated and feeling the heat say nothing about your UV dose: you can be drenched in sweat and still burning, so reapplication and shade — not water bottles — prevent sunburn.
What the evidence actually says — Skin Cancer Foundation — Sun protection basics

Questions we get a lot

Does drinking water prevent sunburn in a heatwave?

No. Hydration helps your body cope with heat, but sunburn is UV damage to the skin — only blocking UV with sunscreen, clothing and shade prevents it. You can be fully hydrated and still burn badly on a hot, sunny day.

How often should I reapply sunscreen when it's extremely hot?

Reapply at least every two hours, and sooner if you're sweating heavily — heat and perspiration wear sunscreen down faster. Reach for a water-resistant, broad-spectrum SPF 30+, and reapply right after toweling sweat off your face.

Is sunscreen still needed if it's overcast during a heatwave?

Yes. Up to 80% of UV passes through clouds, and UVA stays fairly constant regardless of cloud cover, so a hazy, oppressive day can still burn skin. Daily broad-spectrum sunscreen, reapplied through the day, is recommended even when the sun isn't visible.

What people keep asking

r/SkincareAddiction: 'It's a heatwave and I'm sweating it all off — how often should I really be reapplying sunscreen?'

Sources & citations

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