Miami is the perfect combination of kid-friendly attractions (animal parks, children's museums) and vast swaths of nature (Everglades National Park) -- plus all that sun! Kids never run out of things to do here. Spanish and Cuban influences give Miami its Latin flair, which shines through especially in the food.
The winter or "shoulder" seasons (late fall, early spring) are ideal for wandering the city in dry and warm (but not too hot) weather. The area used to shut down to tourists in the muggier summer, but in recent years it's become a more year-round attraction. That said, prepare for heat and afternoon rain if you come in summer. Getting up and out as early as possible will help you navigate around the less favorable weather conditions of this time.
Bring plenty of shorts in summer, and a few pairs of pants in winter (family tourist attire here is mostly flip-flop casual). In the summer months, you'll definitely need to slip a rain poncho or umbrella into your suitcase. Late summer and early fall is also peak hurricane season in Miam. Get more weather info.
Miami International Airport (MIA) is the major airport in the area. But the Ft. Lauderdale-Hollywood International Airport (FLL) is only a 45-minute drive, so consider arriving there if you can get a better flight. Taxis (and hotel shuttles) can take you to your hotel. Public transportation is weak in South Florida so you'll need to rent a car if you want to see the sites. You can also get to Miami by driving, winding down the (long) I-95 or I-75 or hopping on an Amtrak train or Greyhound bus.
Parking can be a challenge in some places in Miami (and hotels often charge a premium for overnight parking). But if your family plans to see lots of sites, you'll need a car. A small number of destinations, including Vizcaya and the Miami Science Museum, are a short walk from the elevated Metrorail system, but the train's limited route means it often doesn't travel where you'll want to go.
In Miami, the winter calendar is especially packed with celebrations. Dates vary each year, so check official event websites or call the Chamber of Commerce.
With the high price of popular attractions, it often pays to comb through the tourist brochures and booklets available at most hotels for discount coupons.