Guide to Key West Weather- Casual Monday Charters

Guide to Key West Weather: A Year-Round Tropical Paradise

Many parts of the country are familiar with the seasons you learned in school: spring, summer, fall, and winter. But Key West is closer to the equator than most of us are used to, and—like everything else—the weather is a little different here. It is, after all, more tropical…that’s why we like it!

But with its tropical nature comes a new set of seasons to worry about, each with its own set of considerations for visitors. So whether you want to head out to a Key West sandbar, snorkel on America’s only coral reefs, or just wander Duvall Street until sunrise, here’s the ultimate guide to Key West weather and seasons.

Two Seasons of Tropical Bliss in Key West

Like most tropical islands, Key West has two seasons: the Wet and the Dry. The difference between the ‘classic’ seasons gets blurry here. The trees don’t lose their leaves in fall, everything’s green and blooming in the winter, and summer mostly just brings hotter temperatures. Snow? Yeah, that’s not a thing in Key West. 

The difference between the Dry and Wet Seasons is measured in relative humidity. If you’ve ever been to Disney World in August, you know what Hell the Wet Season in Florida feels like. It’s so humid that you walk outside and are immediately dripping with sweat. So hot that your leather car seats give you second-degree burns. So humid, wet, and sticky that you long for a rainstorm to dry things out. 

Thankfully, we don’t live in Hell Orlando. Even during those humid summer months, the island of Key West has a lovely cooling sea breeze to moderate the temperature. All that humidity does increase the odds of an afternoon thunderstorm or rain shower.

When’s the Best Month to Go to Key West?

If you choose based on what’s most popular, the high season in Key West is during the winter—between November and February. This is when most things are at their most expensive, everything is busy, and the weather is absolutely spectacular. 

The low season is during the late summer and fall, from August through October. It’s hot and humid, although not nearly as bad as many people make it sound. It is the peak of hurricane season, so you must be flexible with your plans. But there are bargains to be had during the low season. 

Shoulder seasons between high and low seasons are popular with visitors looking for a quieter time and great weather. The spring months, from March through May, offer a great balance of good weather and minimized crowds.

Remember that any holiday weekends are busy in Key West, regardless of the time of year. Key West Mini-Season is one of the most popular times to visit the island, particularly if you’re hungry for lobster. 

Key West Weather by Month

Month to month, season to season, everything changes in Key West. Well, okay, it doesn’t really change much. The palm trees are green, the beach is sandy, and the sea is reasonably warm all 12 months of the year.

Winter in Key West

Winter is all about perspectives in Key West. With every cold front, locals bundle up in their heaviest hoodies and complain that afternoon high temps have dipped below 70 degrees. How dare they! Conchs know it comes every year, so they have a stash of jeans and sweatshirts for those cold days. Flip-flops, however, never go out of style here. 

Meanwhile, tourists from up north are sunning on the beaches, having the time of their lives. Seventy degrees feels sublime because they just got off a plane that had to be de-iced; it was five below back in Poughkeepsie last night. 

Cold fronts bring chilly weather and gusty, northerly winds to the island for a few days at a time. The front is usually marked by a line of showers or thunderstorms that quickly pass. In between, things warm up into the high 70s/low 80s, and life returns to normal. These mostly dry conditions make up the Key West dry season.

The Key West water temperature during the winter is the coldest all year, usually in the low to mid-70s. If you’re going on a snorkel or dive charter and planning to spend long periods of time in the water, you might want to consider at least a shortie-style wetsuit. Key West water temps usually bottom out sometime in February and start climbing for the rest of the year. 

Key West Weather in January

When the giant conch drops on New Year’s Eve, it brings the coldest month of the year. Despite what you may hear online, wearing socks with flip-flops is the only reasonable course of action during January. 

Key West Weather in February

Look at that; there’s snow in the forecast! No, not in Key West. Just everywhere else. Fun fact: Key West is one of the only American cities with no record of ever having any snow, sleet, ice, or even frost. Not even a flurry.. 

Key West Weather in March

March is the height of misery for most people up north. The snow is slushy, mud-colored, and everlasting; everyone you know is on an island somewhere. Make your island Key West, and you’ll be treated to 80-degree weather and 75-degree, clear tropical water. March is definitely one of the best months to visit Key West. 

Average high temperature 76º
Average low temperature 66º
Average water temperature 69º
Average sunset time in Key West 5:53 pm

Average high temperature 77º
Average low temperature 67º
Average water temperature 70º
Average sunset time in Key West 6:10 pm

Average high temperature 80º
Average low temperature 69º
Average water temperature 75º
Average sunset time in Key West 6:27 pm

Spring in Key West

Spring brings a moderation of the weather, but all in all, it’s not much different than winter. Cold fronts start getting less and less frequent as summer approaches. With fewer fronts, daily high temps rise steadily but are nicely moderated by the island’s sea breeze. 

The spring water temperature in Key West warms gradually, reaching 80 degrees or so by early May. The spring months also have some extra low tides that make for great sandbar hopping. 

Key West Weather in April

April sits right in the sweet spot of perfect times to visit Key West. Now that daylight savings has started, the sunset is a little later, and you have more time to explore during the day. The temperatures are pleasant and warm, and even the water is nice enough for long swims. It’s even warm enough that you might convince some locals to get in with you. 

Key West Weather in May

May is one of the favorite times of year to visit Key West because it’s still pleasant and spring-like. Plus, the tropical storms haven’t yet had a chance to form. 

Key West Weather in June

By June, summer is officially starting to arrive in Key West. High temperatures are getting above 90 degrees, and the water is a balmy 86 degrees. Of course, there are plenty of island breezes and frosty beverages to keep you comfortable. 

June 1 officially starts the Atlantic hurricane season, but storms that form this early are seldom more than rain events. 

Average high temperature 83º
Average low temperature 73º
Average water temperature 79º
Average sunset time in Key West 7:40 pm

Average high temperature 86º
Average low temperature 76º
Average water temperature 83º
Average sunset time in Key West 7:54 pm

Average high temperature 89º
Average low temperature 79º
Average water temperature 86º
Average sunset time in Key West 8:16 pm

Summer in Key West

Summer is the height of Florida’s rainy or wet season. All the rain comes from two sources: afternoon thunderstorms and tropical systems. However, Key West is relatively dry during the rainy months compared to the rest of the state. 

Every afternoon, the sun warms the land, making the air rise. Clouds form over the islands and mainland Florida. By noon or so, these clouds are towering cumulus, rising tens of thousands of feet. With enough energy, they’re well on their way to becoming airmass thunderstorms and dumping a ton of rain wherever they go. It happens every afternoon on the mainland but only occasionally in Key West. 

Tropical systems are born over the hot ocean waters of the Gulf of Mexico, Atlantic Ocean, and Caribbean Sea. Most tropical systems are not much more than a few days of rainy weather. It’s called the wet season, after all. 

Key West water temperatures reach their highest of the year during the summer, with temperatures between 80 and 85 degrees even out at the reefs. While that sounds quite warm, it’s a great time of year to try snorkel trips and explore new underwater spots. 

Key West Weather in July

The only way to view fireworks is from a boat in Key West, just sayin’.

Key West Weather in August

August is getting hot, with average highs above 90 and the tropics heating up. Still, 90 doesn’t feel as bad as it sounds when you’re sitting on a sandbar somewhere. The peak weeks of hurricane season start in mid-August and run through October.

Key West Weather in September

With the kids gone back to school, hurricanes out on the ocean, and enough humidity to cook your sous vide, September is historically the quietest month in Key West. It’s not a bad time to visit if you like things all to yourself. September 10 marks the peak of hurricane season.

Average high temperature 90º
Average low temperature 81º
Average water temperature 87º
Average sunset time in Key West 8:18 pm

Average high temperature 91º
Average low temperature 81º
Average water temperature 87º
Average sunset time in Key West 8:01 pm

Average high temperature 89º
Average low temperature 79º
Average water temperature 86º
Average sunset time in Key West 7:36 pm

Fall in Key West

It takes the ocean a while to lose all the heat it built up over the summer, so temperatures and weather are still moderate in Key West during the fall. With each passing month, cold fronts start becoming more frequent, and temperatures gradually fall. Expect daily highs to range anywhere from the low 70s after a front to the high 80s in between cold spells. 

Hurricane season does not officially end until the last day of November. Storms at this time of year can track all the way across the Atlantic from the coast of Africa. Flexibility is the name of the game because visitors will be asked to evacuate if a storm looks certain to track toward the island.

 

Key West water temperature during the fall starts dropping off after its summer highs. Expect temperatures to still be above 80 for most of the time, however. Toward December, it will fall to the mid-70s.