USDA Hardiness Zone 11b
Frost Dates for 33040 — Key West, Florida
NOAA 1991–2020 normals from Key West International Airport, FL (4 ft), under a mile south.
Updated
No night at or below 32°F was recorded at Key West International Airport, FL in 1991–2020, not even 36°F, so Key West has no frost dates to plan around; the coolest month, January, averages a low of 66°F.
- Winters with a freeze
- 0%
- Winters with 36°F
- 0%
- Coldest month low
- 66°F
- Hardiness zone
- 11b
32°F or below, 1991–2020
frost possible on leaves
average, January
45 to 50°F (7.2 to 10.0°C) coldest night
Frost risk by date in Key West
Key West International Airport, FL, in Key West, did not record a night at or below 32°F in 1991–2020. 13 of the 158 other Florida stations behind this site's ZIP pages recorded no 32°F night either.
Freeze probabilities 1991–2020 at Key West International Airport, FL, from NOAA NCEI U.S. Climate Normals. Where a temperature is reached in fewer than 99.5% of years, the dates describe only the years that reach it. Not a forecast.
Frost risk on any date in 33040 →Compare Key West with another place →
Weather by month in Key West
August is the warmest month at Key West International Airport, FL, averaging 91°F by day and 81°F at night; January is the coldest at 76°F and 66°F. Not one month recorded a 32°F night; the lowest monthly average low is 66°F.
Warmth for growing adds up to 10,548 growing degree days a year (base 50°F), the most of the 158 Florida stations. 46% of them (4,844) have built up by the end of June, and August adds the most, 1,102. Precipitation totals 40.4 inches a year, most in September (7.2") and least in February (1.5"); May to September bring 58% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 76 | 66 | 1.8 | 0% | 0 | 640 |
| Feb | 77 | 67 | 1.5 | 0% | 0 | 623 |
| Mar | 80 | 69 | 1.5 | 0% | 0 | 758 |
| Apr | 83 | 73 | 2.1 | 0% | 0 | 836 |
| May | 86 | 76 | 3.1 | 0% | 0 | 966 |
| Jun | 89 | 79 | 4.2 | 0% | 0 | 1022 |
| Jul | 90 | 81 | 3.6 | 0% | 0 | 1097 |
| Aug | 91 | 81 | 5.4 | 0% | 0 | 1102 |
| Sep | 89 | 79 | 7.2 | 0% | 0 | 1023 |
| Oct | 86 | 77 | 5.7 | 0% | 0 | 970 |
| Nov | 81 | 72 | 2.1 | 0% | 0 | 798 |
| Dec | 78 | 68 | 2.2 | 0% | 0 | 713 |
Monthly normals 1991–2020 at Key West International Airport, FL (4 ft), NOAA NCEI. "32°F night": chance of at least one in the month. GDD: growing degree days, base 50°F.
Compared with the next station
The nearest other station, Bahia Honda Sp, FL, 31 miles east of Key West, has no 32°F night on record either, and a coolest-month low 2°F colder (64°F).
Where these figures come from
ZIP 33040 is under a mile from Key West International Airport, FL, which stands at 4 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 33040 in zone 11b, the band where the coldest night of the year averaged 45 to 50°F (7.2 to 10.0°C) over 1991–2020; a zone describes winter lows, not frost dates.
Hardiness zone and temperature range: USDA Plant Hardiness Zone Map 2023 (USDA-ARS, Oregon State University), ZIP-code listing, unchanged. °C converted from °F by this site.
Thirty-year averages, not a forecast: check the forecast before planting out. How stations are matched and which pages are offered to search engines: methodology.