The Everglades operates on a rhythm dictated less by the traditional four seasons of the northern hemisphere and more by the rise and fall of water. As a subtropical wilderness, its climate is divided into two dominant phases: the Dry Season (November to April) and the Wet Season (May to October). Understanding these cycles is essential for comprehending how this "River of Grass" breathes.
The Dry Season (November – April)
This is the most popular time for visitors, characterized by low humidity, clear blue skies, and mild temperatures. During these months, the Everglades undergoes a profound transformation as the water levels across the sawgrass prairies drop significantly.
- Atmospheric Character: Highs typically hover between 77°F (25°C) and 82°F (28°C), while evening lows can dip into the 50s°F (12°C-15°C). The air is crisp and dry, a sharp contrast to the rest of the year.
- Wildlife Convergence: Because the water recedes into deep "alligator holes" and sloughs, wildlife becomes highly concentrated. This season offers a "meet-and-greet" atmosphere where alligators, wading birds, and turtles gather in the few remaining deep-water pools.
- The Feel: It feels vibrant and refreshing. The lack of biting insects—which thrive in standing water—makes the outdoor experience far more approachable.
The Wet Season (May – October)
In May, the atmosphere shifts. The humidity rises sharply, and the sky becomes a theater for dramatic meteorological displays. This is when the Everglades truly earns its reputation as a lush, primeval wetland.
- Daily Rhythm: Mornings often start clear and still. By 2:00 PM or 3:00 PM, towering cumulonimbus clouds build over the interior. Intense, localized thunderstorms typically roll through, providing a brief but violent deluge and a temporary drop in temperature before the sun returns to create a thick, sauna-like steam.
- Subtropical Heat: Daytime temperatures frequently reach 90°F to 95°F (32°C-35°C), with humidity levels often exceeding 90%. The heat index—what it "feels like"—can easily surpass 100°F (38°C).
- Ecosystem Rebirth: The rains replenish the sheetflow, causing the water to spread across the landscape. Wildlife disperses deep into the park, and the sawgrass turns a brilliant, electric green.
Microclimates and Regional Variations
Although the Everglades appears flat, its climate varies between the coast and the interior:
- Coastal Regions (Flamingo & Everglades City): Areas bordering the Gulf of Mexico and Florida Bay benefit from sea breezes. These winds can moderate the afternoon heat but also bring sudden squalls from the open water.
- The Deep Interior (Shark Valley): Away from the cooling influence of the ocean, the interior experiences more stagnant air and higher heat retention. Here, the transition between land and water creates its own localized humidity pockets.
Notable Weather Phenomena
- Tropical Cyclones: Hurricane season runs from June 1 through November 30. While direct hits are infrequent, the threat of tropical storms brings high winds and massive surges of freshwater that are vital for the health of mangrove forests but can lead to park closures.
- Continental Cold Fronts: During the dry season, strong cold fronts from the north can occasionally push all the way to South Florida. These rare events can drop temperatures near freezing for a night or two, a shock to the tropical flora and fauna.
- The Afternoon Monsoon: The consistency of summer afternoon rain is so predictable that locals often set their schedules by it, knowing the "daily wash" will clear the air for a stunning, multi-hued sunset.
Historical Context and Local Adaptation
Historically, the Everglades was a vast, uninterrupted flow. Modern drainage and canal systems have made the region more susceptible to drought during the dry season, leading to occasional wildfires in the sawgrass. Locals and park rangers monitor these cycles closely; a “wet” dry season or an unusually dry “wet” season can disrupt nesting cycles for endangered birds like the Wood Stork, highlighting how deeply the biology of the region is tied to the predictability of its weather.