I have a 2005 Vue 3

I have a 2005 Vue 3.5 V6. My Vue sits outside overnight. I live in a cold weather climate. When I start it in the morning, it starts just fine. It sounds like it started in the cold, until it has had a while to warm up. It goes into gear just fine. When I start driving it, the first shift is a little harder than the others. And only the first shift, for the first time driving it during the day. The RPM's sort of linger around 3,000, then it sort of lunges as it shifts gears.

I had the transmission fluid replaced and it did not really make much difference. Could this something due to the cold weather climate I live in or is something wrong with the transmission?

thanks