Hi, Kiara!
What a wonderful place to celebrate your son's birthday! Walt Disney World, here you come!
Regarding clothing, bring layers. According to Weather.com, the average early November high is around 80 degrees, while the average low is 60. For us, that means a light jacket for cool mornings and evenings, but shorts and T-shirts for warm afternoons. We bring at least one pair of long pants per person, too, in case there is a cold snap, plus socks and closed-toe shoes; it's better to be prepared for both chilly and hot, since you might even get a dose of each on that same trip! Bring swimsuits, too, because it will surely be warm enough to swim, especially because the resort pools are heated year-round.
Because your birthday boy is a Cars fan, I'd suggest that you book your stay at
Disney's Art of Animation Resort. The newest of WDW's Value Resorts, AoA Resort boasts Cars Family Suites, an entire section of suites which are cleverly themed to your son's favorite film From bathroom fixures to mini-kitchen details, the pool area and more, your son will know that THIS vacation was planned all for him.
Send more questions as you think of them, Kiara! We love to help!
And be sure to wish your son a very happy birthday from all of us on the Disney Parks Moms Panel!