Key West (FL) Temperature by Month

Key West in Florida, United States of America sees moderate seasonal temperature shifts, with daytime highs between 24°C (75°F) in January and 32°C (90°F) in August, averaging 28°C (82°F) annually. Explore the full monthly breakdown below.

Key West experiences balanced seasonal shifts, with noticeable but moderate temperature variations. At night, minimum temperatures range from 27°C (81°F) in August to 19°C (66°F) in January.

The chart below illustrates the average maximum day and minimum night temperatures in Key West by month:

The coldest point of the day usually falls between 4 AM and 6 AM, with temperatures peaking around 3 PM. August, the city's warmest month, gets 309 hours of sunshine.

The chart below shows the average temperature throughout the year:

Key West's average annual maximum temperature is 28°C (82°F). To put that in context, here's how it compares to a few well-known destinations:

Rome, Italy averages 20°C (68°F) annually, with reliably warm summers and comfortable winters.

Zermatt, Switzerland averages just 4°C (39°F) annually due to its altitude, with very cold winters and cool summers even at its warmest.

Buenos Aires, Argentina averages 23°C (73°F) a year, with hot summers and mild winters, and seasons reversed compared to Europe.

Tokyo, Japan averages 21°C (70°F) a year, with hot summers, cool winters, and a well-defined cherry blossom spring.

Temperature alone doesn't tell the whole story, humidity plays a big role in how warm or cold it actually feels. High humidity in summer makes the heat feel more intense, particularly once temperatures climb above 25°C. In winter, the same humidity can make cold air feel sharper than the thermometer suggests.

In Key West, January is the coolest month, with average highs of 24°C (75°F) and humidity around 75%, considered high. In August, the warmest month, temperatures average 32°C (90°F) with 73% humidity, conditions that feel high. For a full picture, see our humidity page.

Climate temperature data is typically calculated as a 30-year average. This smooths out year-to-year variability and gives a more reliable picture of what a place is actually like, rather than what happened in any single unusual year.

The readings come from a range of sources, land-based weather stations, ocean buoys, ships, and satellites. That data is collected by weather services around the world, then pooled, quality-checked, and averaged to produce the climate records you see here.

Whether a city sits on the coast or deep inland makes a significant difference to its climate. Coastal areas tend to have more stable temperatures year-round, large bodies of water absorb heat slowly in summer and release it gradually in winter, keeping extremes in check. Cities far from the sea don't benefit from that buffer, which is why continental climates tend to have hotter summers and colder winters than their coastal counterparts at the same latitude.

For more on Key West's weather, including monthly rainfall, sunshine hours, and humidity, visit our Key West climate page.