I'm in NJ. To me it doesn't matter until the temp gets up into the 90's outside and the cheap ass gym owner barely has the AC on. Other than that the gym is the same temp. just maybe more psyched to lift in the summer since we're not all covered up .
For some reason I always do better when it is cold outside, and nice insde the gym. Im not realy sur why though. Pa weather is always tricky though, you never know what the year will bring.
It seems like winter lasts for at least 9 months up here in MN. I seem to have better workouts when it's cold outside because I'm in no big hurry to go back out there. Plus shoveling snow is a good pre-workout. lol