There is a temp range that you have to avoid when combining in snow. I dont remember the exact temp range, but something like below 20 and above 40 works fine. Between 20 and 40 is like bending over and asking the neighborhood bully to give you a swift kick in your bottom side. We found that picking after 7PM and before 7AM helped.
You just have to wait until the snow gets off the ears and stalks. Then combine at night when its below 20* and stat out of the snow. Good luck. I haven't had to do it in a while, hope I don't have to do it again, Jim.
If it's not cold enough to gel your diesel fuel, it's not cold enough to combine in the snow. When we've had to do it (with FKS in early 80's) it had to be closer to zero degrees F.