Pole only slippery at night, lol

Anyone else have this issue? My brass is SO grippy during the day and in the morning, and especially if it's cooler or humid sticky weather.  But in the evenings it's slippery as chrome! It's so weird! I can mend the situation with mighty grip, and besides I hardly ever pole at night, I'm a morning poler, but I just found it strange! Unless it's my hands and not the pole, lol