[sevenseacat]

That's basically sun up to sun down, here.

It's been completely grey, overcast, and raining here all day and the UV index sat between 3 and 5.

[flyingshelf]

The worst sunburn I ever got was on a boat while overcast. I don't trust them clouds no more.

[plorkyeran]

Clouds block a decent amount of UV on average, but it’s much less consistent than you might expect. 9/10 you might be completely fine with no sunscreen and then get a horrible sunburn the tenth, with no apparent visual distinction between them.

[Zenbit_UX]

Ya, the relationship between UV and sunlight is strange and unintuitive. For that reason I use a UV widget on my lock screen.

I find that being exposed to the value (e.g. 4) while being able to see the suns effect (e.g. cloudy) gives me a better feel for conditions.