Does the Sun Burn the Same Year-Round? A Season-by-Season UV Guide
Sun protection isn't a summer-only chore — here's how UVA and UVB behave across the calendar and why winter skin still needs SPF.
UVB radiation peaks in mid-summer at temperate latitudes, while UVA radiation stays relatively constant all year — which is why cumulative skin damage continues through fall and winter even when sunburn risk drops.
The World Health Organization and skin-cancer authorities emphasize that UVA exposure is steady across seasons and penetrates clouds and glass, so the absence of a summer-style burn does not mean the absence of damaging UV.
Questions we get a lot
Is UV stronger in summer than winter?
UVB, the burning ray, does peak in mid-summer at temperate latitudes, so sunburn risk is highest then. But UVA stays relatively constant all year, meaning skin damage continues through fall and winter. The seasonal drop in burn risk does not mean UV exposure disappears.
Do I need sunscreen on cloudy or winter days?
Yes. UVA penetrates clouds and window glass and remains fairly steady year-round, so overcast and cold days still deliver damaging UV. Daily broad-spectrum sunscreen guards against that constant UVA load. The World Health Organization notes UV exposure is not limited to bright, hot days.
What's the difference between UVA and UVB across the seasons?
UVB drives sunburn and varies strongly with season and time of day, peaking in summer. UVA is associated with aging and long-term damage and stays relatively constant throughout the year. Because of UVA's persistence, year-round broad-spectrum protection makes sense.
r/SkincareAddiction: 'Do I really need sunscreen in winter if it's cold and cloudy and I'm not getting any sun?'