Harwich, MA climate
Harwich has chilly winters and pleasant summers. A typical July afternoon reaches 78°, a January night drops to 25°, and about 25 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Harwich feels like
Winter
Spring
Summer
Fall
Harwich 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° | 25° | 3.9" | 7.5" | 12 | 7 | 23° – 38° |
| February | 40° | 26° | 3.3" | 9.9" | 11 | 8 | 23° – 39° |
| March | 44° | 31° | 4.3" | 3.8" | 12 | 4 | 32° – 43° |
| April | 53° | 39° | 4.1" | 0.5" | 12 | 0 | 42° – 49° |
| May | 62° | 47° | 3.2" | 0 | 11 | 0 | 50° – 58° |
| June | 71° | 57° | 3.3" | 0 | 10 | 0 | 60° – 67° |
| July | 78° | 63° | 2.4" | 0 | 8 | 0 | 67° – 74° |
| August | 77° | 63° | 3.5" | 0 | 8 | 0 | 67° – 74° |
| September | 71° | 57° | 3.7" | 0 | 9 | 0 | 61° – 68° |
| October | 62° | 47° | 4.3" | 0 | 11 | 0 | 51° – 61° |
| November | 52° | 39° | 4.0" | 0.2" | 11 | 0 | 42° – 49° |
| December | 44° | 31° | 4.7" | 2.6" | 13 | 2 | 32° – 47° |
| Year | 58° | 44° | 44.8" | 24.5" | 127 | 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 Harwich
Harwich gets 45 inches of rain and melted snow a year. December is the wettest month and July the driest. Rain or snow falls on about 127 days a year. Snow covers the ground about 21 days of the year.
About 204 frost-free days a year
In half of years the last 32° night comes by April 13 and the first one by November 3. That leaves about 204 frost-free days for gardens, longer than 75% of U.S. towns.
Heating and cooling a home in Harwich
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Harwich, 93% of that work is heating and 7% 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.
Harwich and its neighbors
Harwich borders 4 towns with climate data. January nights across them vary by 1.2°. Brewster has the coldest January nights (24°) and Dennis the hottest July afternoons (79°). Harwich’s January low is 25° and its July high 78°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How Harwich 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 Harwich averaged 2.1° warmer than the 1900s. The biggest change is in December (+3.5°). The shift is larger than in 95% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Harwich’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. January swings the most: between 1991 and 2020 its average temperature ranged from 23° to 38°. September is the most reliable, staying within 7°.
Common questions about Harwich’s climate
What is the coldest month in Harwich?
January, with a typical high of 39° and a low of 25°.
What is the hottest month in Harwich?
July, with a typical high of 78° and a low of 63°.
How much snow does Harwich get?
About 25 inches in a normal winter, most of it in February.
When is the first frost in Harwich?
In half of years the first 32° night comes by November 3, and the last spring frost by April 13.
What is the rainiest month in Harwich?
December, with 4.7 inches of rain and melted snow. The year totals 45 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Harwich itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Chatham, MA (6 mi, snow) and West Harwich, MA (3 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.