Photo: Unknown authorUnknown author · Public domainMidwinter lows in Swanzey sink below those of 90% of U.S. towns
On a normal July day the thermometer tops out near 83°. Winter and summer sit 70° apart. By July afternoons alone, it runs cooler than 74% of U.S. towns. Radiators earn their keep from October to April, the months that average under 50°.
A year in Swanzey at a glance
Each month’s typical high and low, and what it brings.
What stands out about Swanzey’s climate
Compared with towns across the U.S., with Swanzey’s place in New Hampshire beside it.
What a year in Swanzey feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 138 frost-free days a year
In half of years the last 32° night comes by May 14 and the first by October 1. Frost and day counts come from NOAA’s station at Keene, NH, 6 miles from the town’s center, 110 ft lower.
The 2023 USDA map puts Swanzey’s center in zone 5b: the coldest night of a typical winter, averaged over 1991–2020, reaches about −12°. 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 73 inches of snow a winter
Snow, measured at Fitzwilliam 2 W, NH, falls mostly in January. Precipitation (rain plus melted snow) adds up to 45 inches a year; October is the wettest month and February the driest. Rain or snow falls on about 104 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Swanzey
95% 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 Keene, NH.
Living with Swanzey’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
138 frost-free days in zone 5b. The last frost comes by May 14 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 1.
Months with highs of 62–84° and lows of 40° or more: May, June, July, August and September. 52 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Swanzey from natural hazards, river flooding is the largest share (80%); heat waves, cold waves, winter storms and ice storms together are 7%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Swanzey and its neighbors
Every town next door is within a degree of Swanzey in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Swanzey’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 |
|---|---|---|---|---|
| Swanzey, NH | 13° | 83° | 45" | 73" |
| Norwich, NY | 14° | 81° | 44" | 75" |
| Warren, PA | 17° | 81° | 45" | 72" |
| Cortland, OH | 18° | 83° | 43" | 68" |
| La Porte, IN | 17° | 83° | 40" | 65" |
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 Swanzey averaged 2.0° warmer than the 1900s. The biggest change is in December (+3.9°).
A bigger shift than in 91% 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 Swanzey compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Swanzey’s place among New Hampshire’s.
Swanzey weather by month
Highs, lows and precipitation from NOAA’s grid at Swanzey’s center; snow, wet days and snow on the ground from Fitzwilliam 2 W, NH. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 32° | 13° | 3.1" | 22.3" | 10 | 25 | 12° – 30° |
| February | 36° | 15° | 2.7" | 16.1" | 7 | 24 | 11° – 32° |
| March | 44° | 23° | 3.2" | 16.3" | 8 | 21 | 26° – 43° |
| April | 57° | 33° | 3.3" | 2.4" | 7 | 4 | 41° – 50° |
| May | 69° | 44° | 3.6" | 0.1" | 10 | 0 | 51° – 62° |
| June | 78° | 53° | 4.4" | 0.0" | 10 | 0 | 63° – 70° |
| July | 83° | 58° | 4.3" | 0.0" | 9 | 0 | 66° – 75° |
| August | 81° | 57° | 4.4" | 0.0" | 8 | 0 | 65° – 73° |
| September | 73° | 49° | 4.2" | 0.0" | 8 | 0 | 57° – 65° |
| October | 60° | 38° | 4.7" | 0.2" | 9 | 0 | 44° – 56° |
| November | 48° | 29° | 3.3" | 1.8" | 8 | 3 | 35° – 44° |
| December | 37° | 20° | 3.8" | 13.3" | 9 | 17 | 22° – 39° |
| Year | 58° | 36° | 45.1" | 72.5" | 104 | 94 |
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 32°. June is the most reliable, staying within 7°.
Where Swanzey’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 Swanzey’s center.
- Snow: Fitzwilliam 2 W, NH.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Keene, NH, 6 miles from the town’s center, 110 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 Swanzey’s climate
What is the weather like in Swanzey?
A typical July afternoon reaches 83°, a January night drops to 13°, and about 73 inches of snow falls in a normal winter. Colder January nights than 90% of U.S. towns; cooler July afternoons than 74% of U.S. towns.
How cold does it get in Swanzey in winter?
January nights average 13°. About 174 nights a year reach 32° or below and 17 reach 0° or below. In the coldest January of the last 30 years the month averaged 12°.
How much snow does Swanzey get?
About 73 inches in a normal winter at Fitzwilliam 2 W, NH, most of it in January, with snow on the ground about 94 days a year.
How hot does it get in Swanzey?
July, with a typical high of 83° and a low of 58°. About 11 days a year reach 90° (Keene, NH).
When is the first and last frost in Swanzey?
In half of years the last spring frost (32°) comes by May 14 and the first fall frost by October 1, about 138 frost-free days, at Keene, NH.
What growing zone is Swanzey in?
Zone 5b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −12°.
What is the best time of year to visit Swanzey?
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 Swanzey getting warmer?
Yes: 1991–2020 averaged 2.0° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 91% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Swanzey.
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.