Key Biscayne, FL climate
Key Biscayne has warm winters and warm summers, with plenty of rain. A typical July afternoon reaches 89°, a January night drops to 62°, and snow is almost unheard of.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Key Biscayne feels like
Winter
Spring
Summer
Fall
Key Biscayne weather by month
Average highs, lows, rain and snow for every month, from NOAA’s 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 76° | 62° | 2.4" | 0 | 8 | 0 | 63° – 73° |
| February | 77° | 63° | 2.3" | 0 | 7 | 0 | 63° – 76° |
| March | 79° | 66° | 2.5" | 0 | 6 | 0 | 66° – 78° |
| April | 82° | 70° | 3.3" | 0 | 6 | 0 | 72° – 81° |
| May | 85° | 74° | 5.6" | 0 | 10 | 0 | 76° – 82° |
| June | 88° | 77° | 8.9" | 0 | 15 | 0 | 80° – 86° |
| July | 89° | 78° | 6.4" | 0 | 15 | 0 | 82° – 85° |
| August | 90° | 78° | 7.8" | 0 | 16 | 0 | 82° – 85° |
| September | 88° | 77° | 8.6" | 0 | 15 | 0 | 81° – 84° |
| October | 85° | 74° | 7.3" | 0 | 13 | 0 | 78° – 83° |
| November | 81° | 69° | 3.4" | 0 | 9 | 0 | 71° – 79° |
| December | 78° | 65° | 2.3" | 0 | 8 | 0 | 61° – 78° |
| Year | 83° | 71° | 60.6" | 0.0" | 127 | 0 |
“Wet days” have at least 0.01" of rain or melted snow. “Snow on ground” counts days with 1" or more. The 30-year range is the coldest and warmest that month’s average temperature got between 1991 and 2020.
Rain and snow in Key Biscayne
Key Biscayne gets 61 inches of rain and melted snow a year. June is the wettest month and December the driest. Rain or snow falls on about 127 days a year.
A year-round growing season
Heating and cooling a home in Key Biscayne
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Key Biscayne, 2% of that work is heating and 98% is cooling, so air conditioning is the bigger bill.
Degree days measure how far each day’s average temperature falls below or rises above 65°, added up over a year. Source: NOAA station normals.
How Key Biscayne compares
Compared with every U.S. town and city on TownTapestry, each counted once.
Warmer than it used to be
The last 30 years in Key Biscayne averaged 2.0° warmer than the 1900s. The biggest change is in February (+2.7°). The shift is larger than in 94% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Key Biscayne’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. December swings the most: between 1991 and 2020 its average temperature ranged from 61° to 78°. August is the most reliable, staying within 3°.
Common questions about Key Biscayne’s climate
What is the coldest month in Key Biscayne?
January, with a typical high of 76° and a low of 62°.
What is the hottest month in Key Biscayne?
August, with a typical high of 90° and a low of 78°. About 55 days a year reach 90°.
How much snow does Key Biscayne get?
Almost none. A normal year brings 0.0 inches.
When is the first frost in Key Biscayne?
Frost is uncommon. Only 0% of years see a night at 32° or below.
What is the rainiest month in Key Biscayne?
June, with 8.9 inches of rain and melted snow. The year totals 61 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Key Biscayne itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Cape Florida, FL (1 mi) away. Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.