Somoresworth High School · Photo: Magicpiano · CC BY-SA 3.0Winter nights in Somersworth are colder than in 88% of U.S. towns
Peak summer warmth arrives in July, with afternoons near 82°. Summers stay cool: July afternoons here are cooler than in 80% of U.S. towns. Warming shows here too: 1.7° more than in 1901–2000, led by December. The frost-free window for a garden runs roughly April 30 to October 9.
A year in Somersworth at a glance
Each month’s typical high and low, and what it brings.
What stands out about Somersworth’s climate
Compared with towns across the U.S., with Somersworth’s place in New Hampshire beside it.
What a year in Somersworth feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 161 frost-free days a year
In half of years the last 32° night comes by April 30 and the first by October 9. Frost and day counts come from NOAA’s station at Rochester Skyhaven Airport, 2.4 miles from the town’s center, 120 ft higher.
The 2023 USDA map puts Somersworth’s center in zone 6a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −8°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 39 inches of snow a winter
Snow, measured at Durham, NH, falls mostly in January. Precipitation (rain plus melted snow) adds up to 48 inches a year; October is the wettest month and February the driest. Rain or snow falls on about 121 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Somersworth
93% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from October through April.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Rochester Skyhaven Airport.
Living with Somersworth’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
161 frost-free days in zone 6a. The last frost comes by Apr 30 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Oct 9.
Months with highs of 62–84° and lows of 40° or more: May, June, July, August and September. 14 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Somersworth from natural hazards, river flooding is the largest share (61%); heat waves, cold waves, winter storms and ice storms together are 10%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Somersworth and its neighbors
Every town next door is within a degree of Somersworth in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Somersworth’s, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| Somersworth, NH | 14° | 82° | 48" | 39" |
| Port Jervis, NY | 17° | 83° | 47" | 43" |
| Carbondale, PA | 16° | 81° | 46" | 47" |
| Watertown, CT | 17° | 83° | 51" | 47" |
| Newton, NJ | 18° | 83° | 47" | 39" |
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 Somersworth averaged 1.7° warmer than the 1900s. The biggest change is in December (+3.3°).
A bigger shift than in 70% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How Somersworth compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Somersworth’s place among New Hampshire’s.
Somersworth weather by month
Highs, lows and precipitation from NOAA’s grid at Somersworth’s center; snow, wet days and snow on the ground from Durham, NH. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 32° | 14° | 3.3" | 10.8" | 9 | 19 | 15° – 30° |
| February | 35° | 15° | 3.3" | 9.1" | 8 | 18 | 11° – 31° |
| March | 44° | 23° | 4.1" | 6.8" | 9 | 14 | 27° – 43° |
| April | 57° | 33° | 4.2" | 1.8" | 11 | 1 | 41° – 49° |
| May | 68° | 44° | 3.7" | 0.0" | 12 | 0 | 50° – 61° |
| June | 76° | 53° | 4.3" | 0.0" | 12 | 0 | 62° – 69° |
| July | 82° | 60° | 3.9" | 0.0" | 11 | 0 | 66° – 74° |
| August | 80° | 58° | 3.6" | 0.0" | 10 | 0 | 66° – 72° |
| September | 73° | 50° | 3.9" | 0.0" | 10 | 0 | 58° – 65° |
| October | 60° | 39° | 4.8" | 0.2" | 10 | 0 | 46° – 56° |
| November | 48° | 29° | 4.1" | 1.3" | 11 | 1 | 34° – 44° |
| December | 38° | 21° | 4.3" | 8.9" | 11 | 11 | 23° – 38° |
| Year | 58° | 36° | 47.5" | 38.9" | 121 | 64 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 11° to 31°. August is the most reliable, staying within 6°.
Where Somersworth’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Somersworth’s center.
- Snow: Durham, NH.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Rochester Skyhaven Airport, 2.4 miles from the town’s center, 120 ft higher; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Somersworth’s climate
What is the weather like in Somersworth?
A typical July afternoon reaches 82°, a January night drops to 14°, and about 39 inches of snow falls in a normal winter. Colder January nights than 88% of U.S. towns; cooler July afternoons than 80% of U.S. towns.
How cold does it get in Somersworth in winter?
January nights average 14°. About 145 nights a year reach 32° or below and 7 reach 0° or below. In the coldest January of the last 30 years the month averaged 15°.
How much snow does Somersworth get?
About 39 inches in a normal winter at Durham, NH, most of it in January, with snow on the ground about 64 days a year.
How hot does it get in Somersworth?
July, with a typical high of 82° and a low of 60°. About 11 days a year reach 90° (Rochester Skyhaven Airport).
When is the first and last frost in Somersworth?
In half of years the last spring frost (32°) comes by April 30 and the first fall frost by October 9, about 161 frost-free days, at Rochester Skyhaven Airport.
What growing zone is Somersworth in?
Zone 6a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −8°.
What is the best time of year to visit Somersworth?
By one simple rule (highs of 62–84° and lows of 40° or more), May, June, July, August and September. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Somersworth getting warmer?
Yes: 1991–2020 averaged 1.7° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 70% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Somersworth.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.