Thanks for coming to planDisney with your question, Catrice!
Halloween time in the Walt Disney theme parks is always so fun! I love all the fall decorations, carved pumpkins, and the special treats.
Beginning September 3, some fun
Halloween Happenings around the Disneyland Park are characters in costume, Haunted Mansion Holiday (I LOVE this A Nightmare Before Christmas overlay!), the Main Street Pumpkin Festival, & Halloween Screams – some nights include fireworks! And, across the way at Disney’s California Adventure Park, you can visit Guardian of the Galaxy – Monsters After Dark, see the Cars characters in costume, check out Luigi’s & Mater’s all decorated for Halloween, and see many other frightful delights around the theme park.
The Oogie Boogie Bash is indeed happening beginning September 3. You can find the party dates
here, so you know when to plan to NOT be in Disney’s California Adventure Park.
I hope this helps with your planning, Catrice! Have a wonderful visit to Disneyland!
Happy Visiting,
Tracy