Brookhaven, NY climate
Brookhaven has chilly, snowy winters and pleasant summers. A typical July afternoon reaches 83°, a January night drops to 23°, and about 32 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Brookhaven feels like
Winter
Spring
Summer
Fall
Brookhaven 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 | 39° | 23° | 3.5" | 10.3" | 11 | 7 | 23° – 37° |
| February | 41° | 24° | 3.2" | 9.4" | 10 | 9 | 21° – 38° |
| March | 48° | 30° | 4.5" | 6.5" | 11 | 4 | 34° – 47° |
| April | 59° | 39° | 4.1" | 0.6" | 11 | 0 | 45° – 53° |
| May | 69° | 49° | 3.5" | 0 | 12 | 0 | 54° – 63° |
| June | 78° | 58° | 4.1" | 0 | 10 | 0 | 65° – 71° |
| July | 83° | 65° | 3.3" | 0 | 9 | 0 | 69° – 77° |
| August | 82° | 63° | 3.8" | 0 | 9 | 0 | 69° – 76° |
| September | 75° | 56° | 3.8" | 0 | 9 | 0 | 63° – 70° |
| October | 64° | 45° | 4.3" | 0 | 9 | 0 | 51° – 61° |
| November | 54° | 36° | 3.6" | 0.5" | 10 | 0 | 40° – 49° |
| December | 44° | 28° | 4.6" | 4.5" | 12 | 3 | 29° – 47° |
| Year | 61° | 43° | 46.3" | 31.8" | 122 | 23 |
“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 Brookhaven
Brookhaven gets 46 inches of rain and melted snow a year. December is the wettest month and February the driest. Rain or snow falls on about 122 days a year. Snow covers the ground about 23 days of the year.
About 193 frost-free days a year
In half of years the last 32° night comes by April 18 and the first one by October 28. That leaves about 193 frost-free days for gardens, longer than 67% of U.S. towns.
Heating and cooling a home in Brookhaven
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Brookhaven, 87% of that work is heating and 13% is cooling, so the furnace matters far more than the air conditioner.
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.
Brookhaven and its neighbors
Brookhaven borders 7 towns with climate data. January nights across them vary by 2.8°. Lake Grove has both the coldest January nights (23°) and the hottest July afternoons (84°). Brookhaven’s January low is 23° and its July high 83°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How Brookhaven 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 Brookhaven averaged 2.3° warmer than the 1900s. The biggest change is in December (+3.6°). The shift is larger than in 99% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Brookhaven’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 29° to 47°. June is the most reliable, staying within 6°.
Common questions about Brookhaven’s climate
What is the coldest month in Brookhaven?
January, with a typical high of 39° and a low of 23°.
What is the hottest month in Brookhaven?
July, with a typical high of 83° and a low of 65°. About 7 days a year reach 90°.
How much snow does Brookhaven get?
About 32 inches in a normal winter, most of it in January.
When is the first frost in Brookhaven?
In half of years the first 32° night comes by October 28, and the last spring frost by April 18.
What is the rainiest month in Brookhaven?
December, with 4.6 inches of rain and melted snow. The year totals 46 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Brookhaven itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Islip Li Macarthur Airport, NY (9 mi, snow) and Shirley Brookhaven Airport, NY (5 mi, frost, heat and degree days). Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.