If I'm actually going to be outdoors for any length of time in winter, nude hose (even layered, as Angie suggests) just won't cut it for me. I need tights.
But if I' m mainly going to be indoors almost the entire time, or it is a mild day, I will wear nude hose. So, like Thistle, I'm more inclined to do it in the early spring -- when I'm craving "light" in general and feel weighed down by opaque darks.
I'll also wear nude hose mid-winter for formal occasions when sheer black or charcoal hose wouldn't look right.
I like patterned hose, too, but they don't always like short-legged me. So I wear those with caution. Coloured hose look a bit clown like on me, alas. Especially with contrasting booties. So typically I default to navy, black, grey, or taupe opaque or near-opaque hose, with booties or boots to match.
If I lived in a more temperate but still not warm climate, like Vancouver's, I would probably wear nude hose a lot more often.