Orlando has a humid subtropical climate — hot summers, mild winters. The best time to visit is late autumn through early spring, roughly November to March, when daytime highs sit in the 70s and 80s°F (20s°C), rain is infrequent, and the theme parks are less punishing to walk around. December and the week around New Year are the single busiest period of the year; plan around the holidays if you can.
Summer (June to September) is hot, humid, and thunderstorm-prone, with afternoon downpours most days. It's also hurricane season, which runs through November. The parks are still fully open but crowds are thick and the heat is draining. January and February tend to be the quietest months, though cold snaps can drop temperatures into the 40s at night.