I, too, realized just last week what a HUGE difference the weather makes in my time! I've been doing a Couch to 5k class at my Y. Two weeks ago, we were jogging 4 minutes then walking 1 minute (repeating 7 times) and I couldn't jog the full 4 minutes each time. The temperature was in the mid-80's. Last week, we concluded our class with a 5k. Having had trouble jogging 4 minutes at a time the week before, I AMAZED myself when I was able to jog the WHOLE first mile! (The temperature was in the mid-70's.) Wow, what a difference the temperature makes!!