Why July UV Is Often Worse Than August
The peak isn't always when you'd expect.
The UV Index is typically highest in late spring and early summer, peaking around the summer solstice, even though the hottest temperatures often arrive weeks later.
Dermatologists point out that UV intensity tracks the sun's elevation, not the thermometer, so the strongest UV of the year often arrives in June and July rather than the hotter weeks of August.
Questions we get a lot
When is the UV index usually highest during the year?
In the Northern Hemisphere, UV typically peaks in late spring and early summer, around the June solstice, when the sun is highest in the sky. That's why July UV is often as strong as or stronger than August, even though the hottest air temperatures frequently come later in the summer.
Why is UV strong even when it doesn't feel hot?
UV intensity depends on the sun's angle and the atmosphere, not on how warm the air feels. Heat lags behind the solar peak by weeks, so a comfortable July day can still carry a very high UV index. Check the index, which most weather apps show, rather than judging by temperature.
When is the UV index high enough to need protection?
Dermatologists generally recommend sun protection whenever the UV Index is 3 or higher. Across much of the US that threshold is reached most of the day through the summer months, so apply broad-spectrum SPF 30+, seek shade around midday and reapply every two hours outdoors.
r/SkincareAddiction: 'Why is the UV index so high in July even on days that don't feel that hot?'