I live in Florida, where it's NEVER below 80% humidity it seems... so I gave up on dope and switched to KlassKote Epoxy colors, and Urethane clear. I can paint in darn near a rain storm with no blush.
Actually, I tell a lie, now that I think on it, I did actually paint during a rain storm once right at the inside edge of my garage opening, and the KlassKote dark blue color did start to blush a little, and I dragged it in the house immediately where the A/C drew the blush out almost instantly. The good news is Epoxy dries slow enough for the moisture/gas to escape before it cures.
But that was such an extreme situation, I mean, it was raining buckets. I was desperate to finish it on a deadline at the time and the rain started after I already mixed the paint and I didn't want to chuck the paint (too cheap). Any other circumstances a sane person would paint in, and this stuff would never blush.
EricV