Choosing between September and October for Disneyland in 2026 involves a tradeoff between crowds and festive atmosphere. Historically, September is the better month for low crowds, particularly the period immediately following Labor Day. During early to mid-September, many schools are back in session, and the "Sunshine Tax" of summer heat begins to fade, though it can still be quite warm. October, however, has become one of the busiest months of the year due to widespread "Fall Breaks" and the immense popularity of Oogie Boogie Bash at California Adventure. While October offers the full "Halloween Time" experience with pumpkins and spooky decor, you will face significantly longer wait times and higher Genie+ (Lightning Lane) prices. If your priority is seeing the most attractions with the least stress, early September is the definitive winner; if you want the ultimate festive vibe and don't mind the "Fall Break" surge, October is your month.