While I'm enjoying gorgeous weather now, summer usually starts in my area around April. I'm trying to find hot weather clothing appropriate for running 10k or more, preferably with a lot of UV protection built in. The two most urgent items I need are moisture wicking underwear and socks, so as to prevent foot yuck and groin irritation.
Once I'm at my target weight, I'll start investing in more pants and shirts, but I have enough to get me through the next few months at least.