This may just be a gross man thing, but whenever I sweat in hot weather, like 85F or more, and there are yellow jackets within 10 feet, they come over and sting me.
Does this happen to anyone else? 6 out of 7 times I have been stung has been, I'm pretty sure, just because I was sweating. This most often happens in August, when temps are high, and YJs are more aggressive too. But on cool days in August, I can go near a nest and nothing happens if I am not sweating. The variable here seems to be the sweat.
Follow-Up Postings:
RE: Anyone attract angry yellowjackets when they sweat?