UVB on Cloudy Day?

I actually have a box turtle, but this section is more active and this is a non species specific question. I just got my boxy and he's but a wee las ( a yearling) so he's only a part-time outsider for now. On some days when I take him out to the pen for his daily dose of sun it's kind of cloudy outside. The question is, since they say you can still get sun burned on a cloudy day, does that mean my lil turtley can get his dosage of UVB rays while it's cloudy?

Yes.

It's possible, but depends on how cloudy or overcast the day is.