Photo: Ascended Dreamer · CC BY-SA 4.0Dunbarton’s winters are colder and snowier than most of the U.S.
A typical July afternoon reaches 82°, a January night drops to 13°, and about 68 inches of snow falls in a normal winter.
A year in Dunbarton at a glance
Each month’s typical high and low, and what it brings.
What stands out about Dunbarton’s climate
Compared with towns across the U.S., with Dunbarton’s place in New Hampshire beside it.
What a year in Dunbarton feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 146 frost-free days a year
In half of years the last 32° night comes by May 8 and the first by October 3. Frost and day counts come from NOAA’s station at Concord Muni Airport, 8 miles from the town’s center, 200 ft lower.
The 2023 USDA map puts Dunbarton’s center in zone 5b: the coldest night of a typical winter, averaged over 1991–2020, reaches about −10°. 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 68 inches of snow a winter
Snow, measured at Concord Muni Airport, is heaviest from January through February, about 17 inches a month. 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 133 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Dunbarton
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 Concord Muni Airport.
Living with Dunbarton’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
146 frost-free days in zone 5b. The last frost comes by May 8 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 3.
Months with highs of 62–84° and lows of 40° or more: May, June, July, August and September. 40 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Dunbarton from natural hazards, river flooding is the largest share (54%); heat waves, cold waves, winter storms and ice storms together are 12%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Dunbarton and its neighbors
Hopkinton has the coldest January nights next door (12°, 1° colder) and Bow the hottest July afternoons (83°, 1° warmer). Differences under a degree are within what the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Dunbarton’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 |
|---|---|---|---|---|
| Dunbarton, NH | 13° | 82° | 48" | 68" |
| Norwich, NY | 14° | 81° | 44" | 75" |
| Bradford, PA | 15° | 80° | 44" | 75" |
| Ellsworth, ME | 11° | 79° | 48" | 75" |
| Cortland, OH | 18° | 83° | 43" | 68" |
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 Dunbarton averaged 1.8° warmer than the 1900s. The biggest change is in December (+3.4°).
A bigger shift than in 76% 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 Dunbarton compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Dunbarton’s place among New Hampshire’s.
Dunbarton weather by month
Highs, lows and precipitation from NOAA’s grid at Dunbarton’s center; snow, wet days and snow on the ground from Concord Muni Airport. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 31° | 13° | 3.3" | 17.1" | 11 | 25 | 12° – 30° |
| February | 35° | 15° | 3.2" | 16.9" | 10 | 24 | 12° – 31° |
| March | 43° | 23° | 3.8" | 13.6" | 12 | 19 | 26° – 42° |
| April | 56° | 33° | 3.9" | 2.5" | 11 | 3 | 41° – 49° |
| May | 68° | 44° | 3.8" | 0.0" | 12 | 0 | 51° – 62° |
| June | 76° | 54° | 4.4" | 0.0" | 13 | 0 | 62° – 68° |
| July | 82° | 59° | 4.1" | 0.0" | 11 | 0 | 65° – 74° |
| August | 80° | 57° | 4.0" | 0.0" | 10 | 0 | 66° – 72° |
| September | 72° | 49° | 3.9" | 0.0" | 9 | 0 | 57° – 65° |
| October | 60° | 39° | 4.9" | 0.8" | 11 | 0 | 45° – 56° |
| November | 47° | 29° | 3.9" | 2.5" | 11 | 3 | 33° – 43° |
| December | 36° | 20° | 4.3" | 14.3" | 12 | 17 | 23° – 38° |
| Year | 57° | 36° | 47.5" | 67.7" | 133 | 92 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 12° to 31°. June is the most reliable, staying within 6°.
Where Dunbarton’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 Dunbarton’s center.
- Snow: Concord Muni Airport.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Concord Muni Airport, 8 miles from the town’s center, 200 ft lower; 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 Dunbarton’s climate
What is the weather like in Dunbarton?
A typical July afternoon reaches 82°, a January night drops to 13°, and about 68 inches of snow falls in a normal winter. Colder January nights than 89% of U.S. towns; cooler July afternoons than 84% of U.S. towns.
How cold does it get in Dunbarton in winter?
January nights average 13°. About 165 nights a year reach 32° or below and 13 reach 0° or below. In the coldest January of the last 30 years the month averaged 12°.
How much snow does Dunbarton get?
About 68 inches in a normal winter at Concord Muni Airport, heaviest from January through February, about 17 inches a month, with snow on the ground about 92 days a year.
How hot does it get in Dunbarton?
July, with a typical high of 82° and a low of 59°. About 14 days a year reach 90° (Concord Muni Airport).
When is the first and last frost in Dunbarton?
In half of years the last spring frost (32°) comes by May 8 and the first fall frost by October 3, about 146 frost-free days, at Concord Muni Airport.
What growing zone is Dunbarton in?
Zone 5b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −10°.
What is the best time of year to visit Dunbarton?
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 Dunbarton getting warmer?
Yes: 1991–2020 averaged 1.8° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 76% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Dunbarton.
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.