Key West, FL weather in August
August in Key West: hot and oppressively humid, with frequent rain. Highs 91°F, lows 81°F, about 15 days with rain. This is the peak of the warm season in Key West.
- Normal high
- 91°F
- Normal low
- 81°F
- Wet days
- 15
- 5.4 in total
- Muggy days
- 31
- dew point 65°F+
How August changes from start to finish
| August 1 | August 31 | |
|---|---|---|
| Normal high | 91°F | 90°F |
| Normal low | 81°F | 80°F |
| Chance of a wet day | 43% | 51% |
| Sunrise / sunset | 6:55 am / 8:11 pm | 7:08 am / 7:46 pm |
| Daylight | 13.3 h | 12.7 h |
Chance of a wet day: average for the first and last 7 days of the month. Times are local clock time (Eastern Time).
A typical August day
- 6 am83°Fdew point 75°F
- 9 am86°Fdew point 76°F
- Noon88°Fdew point 76°F
- 3 pm88°Fdew point 76°F
- 6 pm86°Fdew point 75°F
- 9 pm84°Fdew point 75°F
NOAA hourly normals (local standard time) from Key West Intl Airport (2 mi away); average wind 8 mph; clear or few clouds in 67% of daytime hours, mostly cloudy or overcast in 18%.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F0 of 31
- Beach dayshigh 80-95°F, under 0.05 in of rain, afternoon wind under 15 mph19 of 31
- Hot dayshigh 90°F or more20 of 31
- Muggy daysdaily mean dew point 65°F or more31 of 31
- Wet daysat least 0.01 in of rain or melted snow15 of 31
- Notable rainat least 0.10 in9 of 31
- Freezing nightslow 32°F or below0 of 31
Average days per August, counted from daily records for each year 1991-2020.
Rain in August
Normal precipitation is 5.4 in; a dry August brings about 3.4 in and a wet one about 6.7 in (25th and 75th percentiles). About 3 days bring half an inch or more, and about 1 an inch or more.
How August varies from year to year
- Warmest August, 1991-20202007: average high 92°F
- Coolest August2012: average high 87°F
- Wettest August2005: 13.5 in
- Driest August2007: 1.2 in
- Highest reading94°F (August 27, 2019)
- Lowest reading72°F (August 24, 2016)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
August compared with July and September
| July | August | September | |
|---|---|---|---|
| Normal high | 90°F | 91°F | 89°F |
| Normal low | 81°F | 81°F | 79°F |
| Wet days | 12 | 15 | 16 |
| Comfortable days | 0 | 0 | 0 |
| Daylight | 13.5 h | 13.0 h | 12.3 h |
Highs change by +1°F from July and -2°F into September.
How Key West ranks in August
- Normal high122nd warmest of 378 cities; 15th of 23 in Florida
- Wet days346th driest of 378
- Comfortable days279th most of 341
What to pack for Key West in August
- Light, breathable clothing – highs near 91°F and about 31 muggy days
- A rain jacket or umbrella – rain on about 15 days
- A swimsuit – about 19 beach days
Heating and cooling
August has 0 heating degree days and 637 cooling degree days (base 65°F), 12% of the year's total heating and cooling demand.
Questions
How hot is Key West in August?
The normal high is 91°F and the normal low is 81°F. From 1991 to 2020 the hottest August reading was 94°F (most recently on August 27, 2019).
Does it rain a lot in Key West in August?
About 15 days in August have at least 0.01 in of precipitation, and the normal total is 5.4 in. The wettest August in 1991-2020 was in 2005 (13.5 in); the driest was in 2007 (1.2 in).
Is August a good time to visit Key West?
August ranks 12th of 12 months on our comfort score for Key West (35 out of 100). It has almost no comfortable days and about 20 days at 90°F or hotter. The best months are January, February and March.
Where the numbers come from
- Temperature, rain, frost dates, humidity and wind by hour and cloud cover: Key West Intl Airport (USW00012836), 1.9 mi E of the city center, 4 ft . NOAA normals and daily records, 1991-2020.
- Daily humidity and wind: Key West International Airport (722010-12836), 1.7 mi E of the city center, 1 ft . Hourly observations, 1991-2020.
- Not available for this location: snowfall and snow depth (no station close enough or similar enough in elevation).