2008 GMC Yukon Bumpy ride in cold temps.

My 2008 Yukon XL Denali has GMC's autoride suspension. I have noticed lately that when the temperature outside drops below 50 degrees, the car's ride becomes harsher. There is increased noise even when hitting minor bumps. I know nothing about auto repair so my only explanation would be could the shocks just be 'cold'? Also, when it is cold outside, no matter the temperature (where I live it doesn't go below 10 degrees very often) if I drive on a very bump road, the ride will actually get better as time goes on. It's as if all the bumps have sort of 'warmed the shocks up.' When the temperature outside is above 50 degrees, the ride is fine. (The ride is just about perfect when its like 70 or above outside). The auto ride I guess is supposed to keep the car level using a computer no matter what the road is like. The car does need a new set of tires and new transmission fluid. The tires it has now are the Bridges tone Dueler h/l Alenza tires.