Be careful with averages especially in Colorado, they are not always indicative of what you'll see. Plan for the worst, and also pack some warm weather clothes. Unit 25 is also one of those where it depends on where you land. If you're down by the river there probably won't be much if anything. On the flip side, chances are that by third season you won't be able to get into the high country because of snow or mud, but you never know!