Monthly weather forecast and climate
Key West, FL

A beach pier in Key West, Florida, with palm trees in the background
A beach pier in Key West, Florida, with palm trees in the background
The climate of Key West is of tropical savanna type (Köppen climate classification Aw); summers are hot, humid, and wet, while winters are warm and relatively dry. The city lies on the southernmost tip of the United States in the Straits of Florida that divides the Atlantic Ocean and the warmer waters of the Gulf of Mexico and has the warmest ocean waters in the United States.

Key West has remarkably sunny weather throughout the year, with a small difference between the mean temperatures of the coldest and the warmest months. Prevalence of sea breezes do not allow average high temperatures to cross 90°F (32.2°C) during the summer, but average low temperatures rarely drop below 80°F (26.7°C). Winter average low temperatures almost never drop below 60°F (15.6°C). Snow and fog are rare in Key West.

The wet season from June to October brings about two-thirds of the 40" (1016mm) of yearly rainfall. Thunderstorms and heavy rains are frequent during the wet season, as Key West is prone to hurricanes like the rest of Florida.
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Key West is a popular tourist destination with pleasant weather from December to May. The best time for a visit is from March to May with smaller crowds and lower rates, as the tourist season usually peaks in February. The spring is noticeably less warm than the summer; the winter is a shade better than spring and is relatively dry. Spring is delightful for swimming with average ocean temperatures of 70°F (21.1°C), and the rain interference is at a minimum.

June to October is the wet season and a time to avoid Key West. September and October is the worst time due to the risk of thunderstorms and hurricanes. Weather changes are sudden, and the mugginess makes the sweltering heat of the summer, which is often 90°F (32.2°C), unbearable. Though Key West receives lesser rain compared to other parts of Florida, almost two-thirds of the annual precipitation occurs in the wet season.

Key West is vulnerable to hurricanes and thunderstorms during the wet season. Although not as vulnerable as Key West, still hurricanes and tropical cyclones linked to the North Atlantic Ocean are dangerous, particularly in the active hurricane season of August to October. These storms occur due to tropical depressions that cause heavy rains and floods in their aftermath. Occasionally, hurricanes with strong winds like the Category 4 Hurricane Irma in 2017 make landfall in the Keys.

January is a delightful month in the mild winter of Key West when the average temperatures are in a comfortable range of 65°F (18.3°C) to 75°F (23.9°C). Weather in January »

Average daily highs are in the range of a warm 76°F (24.4°C) with the abundant daily sunshine of 8 hours. February is also the driest month of the year with the rain gauge registering a lowly 1.5" (38.1mm). Weather in February »

The start of spring in March is the best time to visit Key West with the drop in tourist numbers and the temperatures averaging a warm 68°F (20°C) to 78°F (25.6°C). Weather in March »

April has perfect weather in the range of 72°F (22.2°C) to 82°F (27.8°C) with little rain and the least amount of humidity of the year at 70%. Key West is sunny with long days during this period, and there is no dearth of outdoor activities for the tourists. Weather in April »

Sunny May is basked in the brilliant daily sunshine of 11 hours with light rain up to 7 days during the month. Average lows and highs are steady between 75°F (23.9°C) to 85°F (29.4°C). Weather in May »

June is a slow season for tourism with the mercury touching an average high temperature of 88°F (31.1°C). Smathers beach is a wonderful place in the warm June weather with plenty of food trucks, and umbrella and chair rentals. Weather in June »

July is hot and humid with regular rainfall. The average daily temperatures are in the range of 80°F (26.7°C) to 90°F (32.2°C) with an uncomfortable mugginess in the atmosphere. Weather in July »

August is a hot summer month with average high temperatures of 90°F (32.2°C). It is rainy as thunderstorms are frequent during the summer. The sun is unrelenting with the ultraviolet index at 11, and the daylight stretches to 14 hours. Weather in August »

September is the worst month to visit Key West with the hurricane season at its peak. It is the wettest month of the year with 6.7" (170.2mm) of rainfall and prone to storms and floods. Weather in September »

October is prone to thunderstorms and hurricanes that make their way from the Atlantic Ocean. The temperatures drop down to an average of 76°F (24.4°C) to 85°F (29.4°C), but it is rainy with 12 days of rain during the month. Weather in October »

The wet season, hurricanes, and thunderstorms bid goodbye to Key West by late November. Average highs drop below 80°F (26.7°C), and the weather starts cooling off quickly. Weather in November »

December is a month in the dry season and is the onset of the mild winter. The average temperatures are in the high 60°F (15.6°C) and 70°F (21.1°C) with a few rainy days. Weather in December »

What is the coldest month in Key West?

The coldest month is January, with an average high-temperature of 74.3°F (23.5°C) and an average low-temperature of 64.2°F (17.9°C).

How many days does it rain in Key West?

In Key West, Florida, during the entire year, the rain falls for 106.4 days and collects up to 40.9" (1038mm) of precipitation.

When is the sea coldest in Key West?

January and February, with an average sea temperature of 71.2°F (21.8°C), are months with the coldest seawater. For most, swimming in 71.2°F (21.8°C) is not an enjoyable activity. Furthermore, controlling your breathing becomes progressively more difficult as the water temperature decreases from 69.8°F (21°C) to 59°F (15°C).

What is the driest month in Key West?

The month with the least rainfall is March when the rain falls for 5.8 days and typically collects 1.6" (40mm) of precipitation.

What is the warmest month in Key West?

The warmest month is August, with an average high-temperature of 89.4°F (31.9°C) and an average low-temperature of 79.5°F (26.4°C).

What month is the sea warmest in Key West?

With an average sea temperature of 86.9°F (30.5°C), August is the month with the warmest seawater in Key West. The surface water temperatures above 86°F (30°C) are arguably considered as unpleasant for swimming, and any intense water activity, as the refreshing effect of water is missing.

What is the rainiest month in Key West?

The month with the most rainfall in Key West, Florida, is September when the rain falls for 16.2 days and typically aggregates up to 6.5" (166mm) of precipitation.
Average temperature - Key West, FL
Average humidity - Key West, FL
Average rainfall - Key West, FL
Average rainfall days - Key West, FL

The month with the highest number of rainy days is September (16.2 days).
The month with the lowest number of rainy days is April (4.5 days).

Average sea temperature - Key West, FL

The best month for swimming (with the highest average sea temperature) is August (86.9°F).
Coldest months (with the lowest average sea temperature) are January and February (71.2°F).

Average daylight / Average sunshine - Key West, FL
Average UV index - Key West, FL