Chatham, NH climate
Chatham has cold, snowy winters and pleasant summers, with plenty of rain. A typical July afternoon reaches 77°, a January night drops to 7°, and about 84 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Chatham feels like
Winter
Spring
Summer
Fall
Chatham 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 | 27° | 7° | 3.8" | 20.6" | 10 | 30 | 7° – 25° |
| February | 30° | 9° | 3.4" | 22.0" | 8 | 29 | 7° – 26° |
| March | 39° | 17° | 4.3" | 16.7" | 9 | 28 | 19° – 36° |
| April | 51° | 28° | 4.9" | 3.5" | 10 | 10 | 36° – 45° |
| May | 64° | 39° | 4.4" | 0 | 11 | 0 | 46° – 56° |
| June | 72° | 48° | 5.2" | 0 | 12 | 0 | 57° – 64° |
| July | 77° | 54° | 4.8" | 0 | 12 | 0 | 61° – 69° |
| August | 76° | 53° | 4.6" | 0 | 10 | 0 | 61° – 67° |
| September | 68° | 45° | 4.3" | 0 | 9 | 0 | 52° – 61° |
| October | 55° | 35° | 6.2" | 0.4" | 11 | 0 | 40° – 53° |
| November | 43° | 25° | 5.1" | 4.2" | 10 | 4 | 29° – 39° |
| December | 32° | 15° | 4.8" | 16.5" | 11 | 21 | 17° – 33° |
| Year | 53° | 31° | 55.6" | 83.9" | 120 | 121 |
“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 Chatham
Chatham gets 56 inches of rain and melted snow a year. October is the wettest month and February the driest. Rain or snow falls on about 120 days a year. Snow covers the ground about 121 days of the year.
About 151 frost-free days a year
In half of years the last 32° night comes by May 5 and the first one by October 5. That leaves about 151 frost-free days for gardens, shorter than 80% of U.S. towns.
Heating and cooling a home in Chatham
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Chatham, 97% of that work is heating and 3% 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.
Chatham and its neighbors
Chatham borders 5 towns with climate data. January nights across them vary by 2.3°. Jackson has the coldest January nights (6°) and Conway the hottest July afternoons (81°). Chatham’s January low is 7° and its July high 77°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How Chatham 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 Chatham averaged 1.8° warmer than the 1900s. The biggest change is in December (+3.9°). The shift is larger than in 84% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Chatham’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 7° to 26°. August is the most reliable, staying within 6°.
Common questions about Chatham’s climate
What is the coldest month in Chatham?
January, with a typical high of 27° and a low of 7°.
What is the hottest month in Chatham?
July, with a typical high of 77° and a low of 54°. About 2 days a year reach 90°.
How much snow does Chatham get?
About 84 inches in a normal winter, most of it in February.
When is the first frost in Chatham?
In half of years the first 32° night comes by October 5, and the last spring frost by May 5.
What is the rainiest month in Chatham?
October, with 6.2 inches of rain and melted snow. The year totals 56 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Chatham itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Bridgton 3 Nw, ME (16 mi) away. Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.