Last summer I stained my fence during what the weather app called a "dry spell." It rained two hours later and now I have these weird drip marks that look like my fence is crying (which, honestly, it probably is). I learned the hard way that "partly cloudy" really means "partly monsoon." So yeah, I'm fully on team "wait forever for the perfect day" now.
My deck staining last spring needed those same dry windows. robin450 has a point about how waiting prevents early wear. The forecast chase is annoying but your future self will thank you.