When I knit in hot weather (or with "heat generating" material), I wash my hands with really cold water, every once in a while.
And I tend to hold my knitting differently. If you keep your hands more open and less to the fabric, they "air out" better and stay more dry.
If the sweat makes the stitches slide harder on the needle, I have a trick that I also put into the tip section here:
rub the needle over your scalp (under the hair) so you get the natural hair grease on the needle. That makes the stitches slide much easier.
Just don't poke yourself!