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Contents
- The climate of Key West
- The best time to visit Key West
- The worst time to visit Key West
- Spring weather in Key West
- Summer weather in Key West
- Autumn weather in Key West
- Winter weather in Key West
- Weather in January
- Weather in February
- Weather in March
- Weather in April
- Weather in May
- Weather in June
- Weather in July
- Weather in August
- Weather in September
- Weather in October
- Weather in November
- Weather in December
- Frequently asked questions
- Average temperature
- Average pressure
- Average wind speed
- Average humidity
- Average rainfall
- Average rainfall days
- Average sea temperature
- Average daylight
- Average sunshine
- Average sunshine days
- Average UV index
- Average cloud cover
- Average visibility
A beach pier in Key West, Florida, with palm trees in the background
The climate of Key West
Key West, Florida, USA is characterized by a Tropical wet and dry climate, as classified by the Köppen climate index with the code 'Aw'. This implies an overarching climate pattern of high temperatures and irregular rainfall distribution throughout the year. Looking at the average weather patterns in Key West, it may be summarized as a city with balmy temperatures that oscillate from 68.5°F (20.3°C) in January up to 85.3°F (29.6°C) in August.
Typically, Key West experiences its highest atmospheric pressure in January, at 30.09 in, while the lowest pressure (29.93 in) is observed in September and October. Wind speeds in the region display minor variations throughout the year, peaking at 14.4mph (23.2km/h) in January and November while slowing down to 9.5mph (15.3km/h) during July. As for the humidity levels, they remain consistently high, hovering between 74% and 78%.
A remarkable pattern in Key West's weather is its rainfall duration rather than volume. Rainfall days throughout the year exceed 20 on average from June through September, though the actual rainfall peaks at 5.12 in during September. Clear skies can typically be expected from February through April, while the cloudiest months are from June through October according to yearly averages.
Typically, Key West experiences its highest atmospheric pressure in January, at 30.09 in, while the lowest pressure (29.93 in) is observed in September and October. Wind speeds in the region display minor variations throughout the year, peaking at 14.4mph (23.2km/h) in January and November while slowing down to 9.5mph (15.3km/h) during July. As for the humidity levels, they remain consistently high, hovering between 74% and 78%.
A remarkable pattern in Key West's weather is its rainfall duration rather than volume. Rainfall days throughout the year exceed 20 on average from June through September, though the actual rainfall peaks at 5.12 in during September. Clear skies can typically be expected from February through April, while the cloudiest months are from June through October according to yearly averages.
The best time to visit Key West
Visitors looking for an optimum balance between warm temperatures and clear skies should consider the period from February to April for their trip to Key West. During these months, the temperature averages between 73°F (22.8°C) and 80.2°F (26.8°C), coupled with the lowest average rainfall for the year at 0.67" (17mm) to 1.54" (39mm) respectively. Cloud coverage drops dramatically during this period, resulting in higher levels of sunshine hours and increased visibility. This period also sees an additional advantage of the sea temperature rising from 71.2°F (21.8°C) to 80.7°F (27.1°C), offering ideal conditions for water-based activities.
The worst time to visit Key West
Despite Key West's year-round warm climate, some months pose challenges due to elevated rainfall and humidity. The period between June and September is marked by high rainfall averages, ranging from 3.46 in to 5.12 in along with an increased number of rainy days, up to 23.1 days. Although the temperatures during this period range from 83.3°F (28.5°C) to 84.4°F (29.1°C), the consistently high humidity levels can make these months quite uncomfortable, potentially hindering outdoor activities. The high level of cloud coverage during this period also limits the amount of sunshine received.
Spring weather in Key West
Spring in Key West, from March through May, is characterized by gradually rising temperatures and a comfortable level of rainfall. The average high temperatures range from 73.9°F (23.3°C) to 80.2°F (26.8°C) over the course of spring. This time also sees a moderate amount of rainfall ranging from 0.67 in to 3.5 in, making it a great time to enjoy the outdoor beauty of Key West.
Summer weather in Key West
Weather in Key West during the summer months of June, July, and August can be challenging due to high rainfall, humidity, and temperatures. Average high temperatures peak from 83.3°F (28.5°C) to 85.3°F (29.6°C), providing a hot and humid environment. Rainfall also increases significantly, peaking at 4.33 in during August and number of rainy days average at over 20.
Autumn weather in Key West
Autumn arrives in Key West with a slight reduction in temperature but frequent rainfall. Average high temperatures during this period are from 84.4°F (29.1°C) to 77.9°F (25.5°C) between September and November. Rainfall remains significant with monthly averages ranging between 4.21 in to 1.46 in. The number of rainy days, though, sees a steady decrease from a high 23.1 days in September to 14.4 days in November.
Winter weather in Key West
Winter in Key West, encompassing December through February, sees temperatures averaging between 72.7°F (22.6°C) to 75.2°F (24°C). Though the temperatures are lower than other parts of the year, they remain comfortably warm for visitors. Reduced rainfall from 1.22 in to 1.34 in, along with fewer rainy days, make winter an appealing time to visit Key West.
Weather in January
January in Key West, Florida, is defined by mild temperatures. Following the cooler months, the climate tends to be more amenable, though there are periods of intermittent rainfall. The month experiences a slight increase in humidity levels. Weather in January »
Weather in February
February ushers in a marginal increase in temperature in Key West, yet it is still within a comfortable range. This mild weather provides an impetus for outdoor activities. Although February remains a humid month, an interesting contrast is evident in the slight drop in wind speed. Weather in February »
Weather in March
March signals the onset of warmer weather. Subtle shifts in weather patterns during this period characterize Key West's transition into its version of the spring season. The weather stability of February is disrupted in March, yet the trend towards occasional rainfall becomes more pronounced. Weather in March »
Weather in April
April in Key West, Florida, sees an uptick in temperature and an increase in rainfall levels, a hallmark of the city's hot, humid and wet climate pattern. Even as the rains intensify, the city dons an aesthetic beauty that is noticeable. Weather in April »
Weather in May
May is the threshold month marking the change from the cooler, drier season to the more humid, active wet season in Key West. This month experiences a significant change with ample rain, resulting in a lush, vibrant atmosphere. Beach-goers and divers find the rising sea temperature inviting. Weather in May »
Weather in June
June is a distinct month for Key West, as the average temperatures now consistently reach past the 80-degree mark, signifying the start of summer. The perpetual humidity, combined with the recurrent rainfall, brings a unique charm to the city. Weather in June »
Weather in July
July weather in Key West exhibits hotter temperatures and higher humidity. However, the sea provides a constant, cooling breeze which moderates the heat. The sunny days and humid evenings become the routine daily weather pattern for July. Weather in July »
Weather in August
August can be deemed as the most active month in terms of weather events in Key West. The intensity of sunlight during day time is counteracted by the occasional thunderstorms which bring respite from the heat. The constant weather changes can sometimes result in unfavorable conditions, but the tropical charm of the city remains intact. Weather in August »
Weather in September
September's weather in Key West, Florida, comes with mixed surprises. The month start signals the approach of the end of the wet, hot season, and people start to look forward to cooler weather. The later parts of the month feature the intense heat lessening gradually. Weather in September »
Weather in October
October brings a refreshing change to the monotonous hot and humid regimen in Key West. This month is a transition period from the scorching summer to cooler autumn temperatures. Albeit marginally, the arrival of October sees a drop in both temperatures and rainfall. Weather in October »
Weather in November
November is the precursor to the winter season for Key West, and the temperatures are noticeably cooler. A perceptible change in the weather, November is dominated by pleasantly mild weather with lower levels of rainfall. This month signals an end to hurricane season and marks the onset of "Florida's winter". Weather in November »
Weather in December
December in Key West, Florida, characteristically enjoys warm, sunny, and dry weather. Although it is winter, the climate remains comfortable, with the sea temperature favorable for water activities. Evenings can occasionally see cooler temperatures, and it is the ideal month for those looking to escape harsh winter conditions elsewhere. Weather in December »
Updated: Aug 6, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the coldest time of year?
January stands out as Key West's coldest month, with an average high-temperature of 72.7°F (22.6°C) and a low-temperature of 68.5°F (20.3°C).
How many days does it rain?
Throughout the year, there are 199.2 rainfall days, and 31.61" (803mm) of precipitation is accumulated.
What months are the ocean coldest?
January and February, with an average ocean temperature of 71.2°F (21.8°C), are months with the coldest seawater.
When is the lowest UV index?
January is the month with the lowest UV index, with an average maximum UV index of 5.
What is the most humid month?
The most humid month is February, with an average relative humidity of 78%.
What is the driest month?
March is the month with the least rainfall. Rain falls for 11.7 days and accumulates 0.67" (17mm) of precipitation.
When is Daylight Saving Time (DST)?
On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts, and the time zone changes from EST to EDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from EDT to EST.
What is the month with the highest UV index?
The months with the highest UV index are April through October, with an average maximum UV index of 7.
When are the longest days?
With an average of 13h and 36min of daylight, June has the longest days of the year.
What are the least humid months?
July through September, with an average relative humidity of 74%, are the least humid months.
What month has the most sunshine in Key West?
July has the most sunshine of the year, with an average of 11h of sunshine.
What is the warmest month?
August stands out as Key West's warmest month, with an average high-temperature of 85.3°F (29.6°C) and a low-temperature of 82.9°F (28.3°C).
What month is the ocean warmest?
The month with the warmest seawater is August, with an average ocean temperature of 86.9°F (30.5°C).
What is the wettest month in Key West?
The month with the most rainfall is September, when the rain falls for 23.1 days and typically aggregates up to 5.12" (130mm) of precipitation.
What is the month with the shortest days?
December has the shortest days of the year, with an average of 10h and 36min of daylight.
What is the month with the least sunshine?
The month with the least sunshine is December, with an average of 6.3h of sunshine.
Average temperature
Key West, FL
The warmest month (with the highest average high temperature) is August (85.3°F).
The month with the lowest average high temperature is January (72.7°F).
The month with the highest average low temperature is August (82.9°F).
The coldest month (with the lowest average low temperature) is January (68.5°F).
Average pressure
Key West, FL
- Average pressure in January:
30.09"Hg - Average pressure in February:
30.08"Hg - Average pressure in March:
30.07"Hg - Average pressure in April:
30.01"Hg - Average pressure in May:
29.99"Hg - Average pressure in June:
29.98"Hg
- Average pressure in July:
30.02"Hg - Average pressure in August:
29.97"Hg - Average pressure in September:
29.93"Hg - Average pressure in October:
29.93"Hg - Average pressure in November:
30.01"Hg - Average pressure in December:
30.06"Hg
The month with the highest atmospheric pressure is January (30.09"Hg).
The months with the lowest atmospheric pressure are September and October (29.93"Hg).
Average wind speed
Key West, FL
- Average wind speed in January:
14.4mph - Average wind speed in February:
13.4mph - Average wind speed in March:
14mph - Average wind speed in April:
13.1mph - Average wind speed in May:
12.2mph - Average wind speed in June:
10.3mph
- Average wind speed in July:
9.5mph - Average wind speed in August:
10.1mph - Average wind speed in September:
10.3mph - Average wind speed in October:
13.7mph - Average wind speed in November:
14.4mph - Average wind speed in December:
13.8mph
The windiest months (with the highest average wind speed) are January and November (14.4mph).
The calmest month (with the lowest average wind speed) is July (9.5mph).
Average humidity
Key West, FL
The month with the highest relative humidity is February (78%).
The months with the lowest relative humidity are July, August and September (74%).
Average rainfall
Key West, FL
- Average rainfall in January:
1.34" - Average rainfall in February:
1.1" - Average rainfall in March:
0.67" - Average rainfall in April:
1.54" - Average rainfall in May:
3.5" - Average rainfall in June:
3.46"
- Average rainfall in July:
3.66" - Average rainfall in August:
4.33" - Average rainfall in September:
5.12" - Average rainfall in October:
4.21" - Average rainfall in November:
1.46" - Average rainfall in December:
1.22"
The wettest month (with the highest rainfall) is September (5.12").
The driest month (with the least rainfall) is March (0.67").
Average rainfall days
Key West, FL
- Average rainfall days in January:
12.3 days - Average rainfall days in February:
11 days - Average rainfall days in March:
11.7 days - Average rainfall days in April:
13.4 days - Average rainfall days in May:
16.5 days - Average rainfall days in June:
19.5 days
- Average rainfall days in July:
20.7 days - Average rainfall days in August:
23.1 days - Average rainfall days in September:
23.1 days - Average rainfall days in October:
20.1 days - Average rainfall days in November:
14.4 days - Average rainfall days in December:
13.4 days
The months with the highest number of rainy days are August and September (23.1 days).
The month with the least rainy days is February (11 days).
Average sea temperature
Key West, FL
The best month for swimming (with the highest average sea temperature) is August (86.9°F).
The coldest months (with the lowest average sea temperature) are January and February (71.2°F).
Average daylight / Average sunshine
Key West, FL
- Average daylight in January:
10h and 5min - Average daylight in February:
11h and 2min - Average daylight in March:
12h and 0min - Average daylight in April:
12h and 4min - Average daylight in May:
13h and 2min - Average daylight in June:
13h and 4min
- Average daylight in July:
13h and 3min - Average daylight in August:
13h and 0min - Average daylight in September:
12h and 2min - Average daylight in October:
11h and 4min - Average daylight in November:
11h and 0min - Average daylight in December:
10h and 4min
The month with the longest days is June (Average daylight: 13h and 36min).
The month with the shortest days is December (Average daylight: 10h and 36min).
- Average sunshine in January:
7h and 1min - Average sunshine in February:
8h and 4min - Average sunshine in March:
8h and 5min - Average sunshine in April:
9h and 4min - Average sunshine in May:
10h and 5min - Average sunshine in June:
10h and 4min
- Average sunshine in July:
11h and 0min - Average sunshine in August:
9h and 4min - Average sunshine in September:
9h and 0min - Average sunshine in October:
7h and 2min - Average sunshine in November:
6h and 4min - Average sunshine in December:
6h and 2min
The month with the most sunshine is July (Average sunshine: 11h and 0min).
The month with the least sunshine is December (Average sunshine: 6h and 18min).
Average sunshine days
Key West, FL
- Average sunshine days in January:
14 days - Average sunshine days in February:
14.1 days - Average sunshine days in March:
17 days - Average sunshine days in April:
13.6 days - Average sunshine days in May:
10.8 days - Average sunshine days in June:
7.6 days
- Average sunshine days in July:
8.5 days - Average sunshine days in August:
6.2 days - Average sunshine days in September:
4.5 days - Average sunshine days in October:
7.2 days - Average sunshine days in November:
11.8 days - Average sunshine days in December:
12.2 days
The month with the most sunshine days is March (17 days).
The month with the least sunshine days is September (4.5 days).
Average UV index
Key West, FL
The months with the highest UV index are April, May, June, July, August, September and October (UV index 7).
The month with the lowest UV index is January (UV index 5).
Average cloud cover
Key West, FL
The month with the most cloud cover is January (Cloud cover 34).
The month with the least cloud cover is April (Cloud cover 23).
Average visibility
Key West, FL
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Key West, Florida, USA
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