Stonington, CT climate
Stonington has chilly winters and pleasant summers. A typical July afternoon reaches 81°, a January night drops to 24°, and about 25 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Stonington feels like
Winter
Spring
Summer
Fall
Stonington 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° | 24° | 3.4" | 5.8" | 11 | 7 | 23° – 38° |
| February | 40° | 24° | 3.0" | 8.3" | 10 | 7 | 20° – 39° |
| March | 47° | 31° | 4.4" | 3.9" | 12 | 3 | 33° – 46° |
| April | 57° | 39° | 4.1" | 0.8" | 12 | 0 | 45° – 52° |
| May | 66° | 49° | 3.5" | 0 | 12 | 0 | 53° – 62° |
| June | 75° | 58° | 3.7" | 0 | 10 | 0 | 64° – 69° |
| July | 81° | 65° | 3.1" | 0 | 10 | 0 | 69° – 77° |
| August | 80° | 64° | 3.6" | 0 | 9 | 0 | 69° – 76° |
| September | 74° | 57° | 4.0" | 0 | 10 | 0 | 63° – 69° |
| October | 63° | 47° | 4.4" | 0 | 10 | 0 | 52° – 61° |
| November | 53° | 37° | 3.6" | 0.5" | 10 | 0 | 41° – 49° |
| December | 44° | 29° | 4.3" | 5.2" | 12 | 4 | 30° – 48° |
| Year | 60° | 44° | 44.9" | 24.5" | 128 | 21 |
“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 Stonington
Stonington gets 45 inches of rain and melted snow a year. October is the wettest month and February the driest. Rain or snow falls on about 128 days a year. Snow covers the ground about 21 days of the year.
About 207 frost-free days a year
In half of years the last 32° night comes by April 8 and the first one by November 2. That leaves about 207 frost-free days for gardens, longer than 76% of U.S. towns.
Heating and cooling a home in Stonington
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Stonington, 88% of that work is heating and 12% 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.
How Stonington 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 Stonington averaged 2.2° warmer than the 1900s. The biggest change is in December (+3.8°). The shift is larger than in 97% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Stonington’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 5°.
Common questions about Stonington’s climate
What is the coldest month in Stonington?
January, with a typical high of 39° and a low of 24°.
What is the hottest month in Stonington?
July, with a typical high of 81° and a low of 65°. About 3 days a year reach 90°.
How much snow does Stonington get?
About 25 inches in a normal winter, most of it in February.
When is the first frost in Stonington?
In half of years the first 32° night comes by November 2, and the last spring frost by April 8.
What is the rainiest month in Stonington?
October, with 4.4 inches of rain and melted snow. The year totals 45 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Stonington itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Groton, CT (8 mi) away. Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.