It will be cool in the morning but hot in the afternoon. Back in 2000 I went the 15th through the 21st of October and it did not rain once. In 2002 I went again in the middle of October, the 19th through the 26th and it rained once for a couple of hours in the middle of the day. I would wear two layers and bring a poncho. You can always rent a locker if you need to.