Dorchester has cold, snowy winters and pleasant summers
A typical July afternoon reaches 78°, a January night drops to 9°, and about 77 inches of snow falls in a normal winter.
A year in Dorchester at a glance
Each month’s typical high and low, and what it brings.
What stands out about Dorchester’s climate
Read from where Dorchester sits among New Hampshire’s towns. The page puts what stands out first.
Living with Dorchester’s climate
What the numbers mean for a garden, a driveway, a furnace and a free afternoon.
127 frost-free days. The last frost comes by May 21 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Sep 26.
About 77" a winter over 21 days with an inch or more, most in February. Snow covers the ground about 106 days a year.
Months averaging under 55° run from October through May. Heating is 97% of the year’s heating-and-cooling load.
About 5 days a year reach 90°, and July afternoons average 78°.
The nicest months are May, June, July, August and September. 111 miles of trails are waiting.
Parks & trails →Normals are averages. Ice storms, nor’easters, floods and heat waves are on the natural hazards page.
Natural hazards →What a year in Dorchester feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
77 inches of snow, 46 of rain and melt
October is the wettest month and February the driest. Rain or snow falls on about 157 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
About 127 frost-free days a year
In half of years the last 32° night comes by May 21 and the first by September 26.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
Dorchester and its neighbors
Rumney has the coldest January nights next door (8°) and Canaan the hottest July afternoons (80°). Tap a town to see its climate.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value. Snow and frost-free days come from the nearest weather station, so neighbors often share them.
Warmer than it used to be
The last 30 years in Dorchester averaged 1.8° warmer than the 1900s. The biggest change is in December (+3.7°).
A bigger shift than in 86% of U.S. towns.
Change by month
How Dorchester compares
Against every U.S. town on TownTapestry, each counted once, with its place in New Hampshire.
Dorchester 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 | 28° | 9° | 3.1" | 17.8" | 12 | 28 | 7° – 26° |
| February | 31° | 10° | 2.6" | 20.2" | 10 | 26 | 7° – 27° |
| March | 39° | 19° | 3.3" | 13.3" | 9 | 24 | 21° – 38° |
| April | 53° | 30° | 3.6" | 3.2" | 11 | 4 | 36° – 46° |
| May | 66° | 41° | 3.8" | 0.1" | 15 | 0 | 47° – 59° |
| June | 74° | 50° | 4.6" | 0 | 16 | 0 | 59° – 65° |
| July | 78° | 55° | 4.7" | 0 | 16 | 0 | 61° – 71° |
| August | 77° | 54° | 4.0" | 0 | 14 | 0 | 62° – 69° |
| September | 69° | 46° | 3.8" | 0 | 11 | 0 | 53° – 62° |
| October | 56° | 36° | 4.9" | 0.8" | 17 | 0 | 41° – 54° |
| November | 44° | 26° | 3.5" | 3.0" | 12 | 3 | 30° – 40° |
| December | 33° | 16° | 3.8" | 18.1" | 13 | 20 | 18° – 35° |
| Year | 54° | 32° | 45.7" | 76.5" | 157 | 106 |
Heating and cooling a home in Dorchester
97% of the work is heating, so the furnace matters far more than the air conditioner.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. Source: NOAA station normals.
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 7° to 27°. August is the most reliable, staying within 7°.
Common questions about Dorchester’s climate
What is the coldest month in Dorchester?
January, with a typical high of 28° and a low of 9°.
What is the hottest month in Dorchester?
July, with a typical high of 78° and a low of 55°. About 5 days a year reach 90°.
How much snow does Dorchester get?
About 77 inches in a normal winter, most of it in February.
When is the first frost in Dorchester?
In half of years the first 32° night comes by September 26, and the last spring frost by May 21.
What is the rainiest month in Dorchester?
October, with 4.9 inches of rain and melted snow. The year totals 46 inches.
Neighbors talk weather
Gardens, snow, and the best days of the year in Dorchester.
Your answer becomes a post in Town Square.
Temperatures and rainfall come from NOAA’s gridded climate normals for Dorchester itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Wentworth, NH (9 mi, snow) and Grafton, NH (13 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. Today’s forecast: National Weather Service.