Generally, during the spring, summer, and fall, I go out a couple days a week and shoot from about 7:30 am till around 7:00 pm (as long as the light is good). Of course, these are the most comfortable, and productive (by total body count) times of the year.
However, during the winter, if you can catch a sunny, warming front after 3-4 days of bitter cold, overcast, and wind.....watch out...you can fry your barrels in short order. The dogs don't stay out for as long as during warm weather, but for the couple hours they are out, they are practically oblivious to everything else except their feeding.
With this "blizzard" that's passed through here yesterday, and the remains of it today, Saturday or Sunday would be awesome pdogging days.
I went out for 3 days just prior to Christmas last year. It had been pretty cold for the few days before that. I shot only about 6 hours each day (the dogs got up late, and retired early), but I did manage to finally kill a .223 barrel on that hunt.
I took a friend on his first pdog hunt in the middle of last February. There was melting snow on the ground. He was using his brand new .204 Ruger, and went through 187 rounds. I thought the shooting was kind of slow, even for February, but he was ecstatic. A monster was created that day. He now has 4 very hi-quality pdog rifles, with glass to match. They are all based off the .204 caliber. He's probably the best shot I've ever met, and he's racked up a heckuva hit rate past 500 yards in a short amount of time.
Mike