I've put in a bit over 57 miles in the last two days -- 32 yesterday and 25 today. Yesterday my average pace was the highest this year on that route (no wind to speak of, just gentle rollers and no real hills) in bright sunshine, 43 degrees. Today I was determined to pass 300 miles for the year to date, so I went out again. My pace ended up about 1 mph slower than the last time I rode the loop. Today's ride was my hilly route with a little over 1300' of climbing under grey skies, 40 degrees. I can definitely feel the difference when I ride with a day or more of rest in between and when I do back to back days. It's mostly manifested by using lower gears on the hills. I'd like to feel as strong on the second day as the first, but that may not happen. Any thoughts?