While Key Largo has fairly consistent weather conditions year-round, its tourist seasons follow a similar trajectory to those in the Caribbean. The absolute peak travel season falls between Christmas holiday and spring break. This time of year offers Key Largo’s most agreeable weather—sunny, with temperatures in the high 70s—as well as the biggest crowds and highest prices for hotels and activities.
There’s also a significant summer high season from June to August that’s especially popular among Floridians because, compared with the mainland, the islands temper the oppressive Florida heat by a few degrees. Northerners, however, will likely still find the summer weather hot and humid, and it’s also the rainiest time of year. During the summer, scuba divers and snorkelers from all around the United States and Europe also flock to Key Largo, when the water warms to the mid-80s, and windless days produce flat-calm seas and unbeatable water clarity on the reefs.
A good alternative to the high seasons is the shoulder season from November to December. During this time, the weather is almost identical to the winter high season, but the crowds have yet to arrive—with the exception of a brief uptick around Thanksgiving—which means better hotel rates and more personalized service on fishing and diving charters.
The September and October low season coincides with the peak of hurricane season. During this time, weather can be hot, muggy, and stormy, and tourist activity slows to a crawl, though with early warning systems and solid evacuation plans, getting caught in a hurricane is unlikely.