it is always easier for me in the winter because my play consists of the simulator and Tiger Woods '11 on PS3 or Wii.
In all seriousness though, the last time I played this year it was about 50* out and my max drive was about 260 yards. That is 20 yards less than my average. Irons were 1 to 1.5 clubs shorter.
You know I forgot all about Tiger Woods on the iPhone. I won the British Open with a -36 the other day. It was boring.