We went to Pisa in early October, and the weather was great. Also, it was not very crowded, and we did no feel crammed into the Tower or rushed in any way. Plenty has been said of the Tower so here is some side information. Get your timed ticket ahead of time. Depending on the crowd, you may not be able to purchase a same-day ticket. You cannot take a bag into the Tower, but there is a secured storage area nearby. Do not wait until the last minute to drop off your bag. It might disrupt your ability to entire on time.