Key West weather by month
Key West runs from about 21°C in February to 29°C in July, with June the wettest month at 300 mm.
warmest month
July
29°C
coolest month
February
21°C
wettest month
June
300 mm
worst air month
June
10 µg/m³
The whole year, month by month.
| Month | Avg temp | Rain | Sun | PM2.5 |
|---|---|---|---|---|
| January | 22°C | 32 mm | 269 h | 7 |
| February | 21°C | 52 mm | 286 h | 8 |
| March | 24°C | 80 mm | 330 h | 8 |
| April | 24°C | 12 mm | 367 h | 7 |
| May | 28°C | 48 mm | 399 h | 9 |
| June | 28°C | 300 mm | 310 h | 10 |
| July | 29°C | 69 mm | 375 h | 9 |
| August | 29°C | 243 mm | 345 h | 7 |
| September | 29°C | 186 mm | 318 h | 5 |
| October | 27°C | 234 mm | 292 h | 5 |
| November | 25°C | 68 mm | 283 h | 6 |
| December | 22°C | 88 mm | 291 h | 7 |
About 3,865 hours of sun a year. Roughly 141 rainy days a year.
These are long-run climate normals, not a forecast. A given year can sit well outside them. PM2.5 is a global model: near the coast it counts sea salt as fine particulate and reads high against ground stations, sometimes by a factor of two. Use the shape of the year, not the absolute number.
where these numbers come from
- · Temperature, rainfall and sunshine: ECMWF ERA5 reanalysis climate normals via Open-Meteo (CC BY 4.0), fetched once and stored.
- · PM2.5: Copernicus CAMS reanalysis, monthly means. Modelled, not station readings; near coasts CAMS counts sea salt as PM2.5 and reads high.
Last reviewed 2026-05-25. Full method, licences and the list of sources we rejected are on the methodology page.