Greenwich, CT climate
Greenwich has chilly, snowy winters and warm summers. A typical July afternoon reaches 85°, a January night drops to 23°, and about 34 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Greenwich feels like
Winter
Spring
Summer
Fall
Greenwich 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 | 30-yr range |
|---|---|---|---|---|---|---|
| January | 39° | 23° | 3.3" | 9.1" | 11 | 23° – 38° |
| February | 41° | 24° | 2.8" | 11.9" | 8 | 20° – 39° |
| March | 49° | 31° | 4.0" | 5.9" | 10 | 34° – 49° |
| April | 61° | 40° | 4.1" | 0.5" | 12 | 46° – 55° |
| May | 71° | 50° | 3.9" | 0 | 12 | 56° – 65° |
| June | 80° | 60° | 4.3" | 0 | 12 | 66° – 72° |
| July | 85° | 66° | 4.4" | 0 | 9 | 70° – 79° |
| August | 83° | 64° | 4.2" | 0 | 9 | 69° – 77° |
| September | 76° | 57° | 4.6" | 0 | 9 | 63° – 71° |
| October | 65° | 45° | 4.4" | 0 | 10 | 51° – 62° |
| November | 54° | 36° | 3.5" | 0.8" | 10 | 40° – 50° |
| December | 44° | 28° | 4.0" | 5.8" | 11 | 29° – 47° |
| Year | 62° | 44° | 47.4" | 34.0" | 124 |
“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 Greenwich
Greenwich gets 47 inches of rain and melted snow a year. September is the wettest month and February the driest. Rain or snow falls on about 124 days a year.
About 200 frost-free days a year
In half of years the last 32° night comes by April 12 and the first one by October 31. That leaves about 200 frost-free days for gardens, longer than 72% of U.S. towns.
Heating and cooling a home in Greenwich
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Greenwich, 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.
Greenwich and its neighbors
Greenwich borders 7 towns with climate data. January nights across them vary by 4.2°. North Castle has the coldest January nights (21°) and Rye the hottest July afternoons (85°). Greenwich’s January low is 23° and its July high 85°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How Greenwich 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 Greenwich averaged 2.2° warmer than the 1900s. The biggest change is in December (+3.6°). The shift is larger than in 97% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Greenwich’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. February swings the most: between 1991 and 2020 its average temperature ranged from 20° to 39°. June is the most reliable, staying within 6°.
Common questions about Greenwich’s climate
What is the coldest month in Greenwich?
January, with a typical high of 39° and a low of 23°.
What is the hottest month in Greenwich?
July, with a typical high of 85° and a low of 66°. About 10 days a year reach 90°.
How much snow does Greenwich get?
About 34 inches in a normal winter, most of it in February.
When is the first frost in Greenwich?
In half of years the first 32° night comes by October 31, and the last spring frost by April 12.
What is the rainiest month in Greenwich?
September, with 4.6 inches of rain and melted snow. The year totals 47 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Greenwich itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Stamford 5 N, CT (7 mi, snow) and Westchester Co Airport, NY (4 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.