Photo: Ascended Dreamer · CC BY-SA 4.0Thetford’s winters are colder and snowier than most of the U.S.
A typical July afternoon reaches 81°, a January night drops to 9°, and about 61 inches of snow falls in a normal winter.
A year in Thetford at a glance
Each month’s typical high and low, and what it brings.
What stands out about Thetford’s climate
Compared with towns across the U.S., with Thetford’s place in Vermont beside it.
What a year in Thetford feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 145 frost-free days a year
In half of years the last 32° night comes by May 9 and the first by October 2. Frost and day counts come from NOAA’s station at Union Village Dam, VT, 3 miles from the town’s center, 370 ft lower.
The 2023 USDA map puts Thetford’s center in zone 5a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −18°. 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 61 inches of snow a winter
Snow, measured at Hanover, NH, falls mostly in January. Precipitation (rain plus melted snow) adds up to 41 inches a year; July is the wettest month and February the driest. Rain or snow falls on about 132 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Thetford
95% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from October through May.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Union Village Dam, VT.
Living with Thetford’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
145 frost-free days in zone 5a. The last frost comes by May 9 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 2.
Months with highs of 62–84° and lows of 40° or more: May, June, July, August and September. 65 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Thetford from natural hazards, river flooding is the largest share (78%); heat waves, cold waves, winter storms and ice storms together are 8%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Thetford and its neighbors
Every town next door is within a degree of Thetford in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Thetford’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 |
|---|---|---|---|---|
| Thetford, VT | 9° | 81° | 41" | 61" |
| Old Town, ME | 9° | 80° | 43" | 75" |
| Canton, NY | 8° | 80° | 39" | 77" |
| Stewartville, MN | 6° | 81° | 36" | 53" |
| Sun Prairie, WI | 10° | 82° | 37" | 52" |
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 Thetford averaged 1.8° warmer than the 1900s. The biggest change is in December (+3.9°).
A bigger shift than in 79% 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 Thetford compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Thetford’s place among Vermont’s.
Thetford weather by month
Highs, lows and precipitation from NOAA’s grid at Thetford’s center; snow, wet days and snow on the ground from Hanover, NH. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 29° | 9° | 2.7" | 16.4" | 11 | 27 | 7° – 27° |
| February | 32° | 10° | 2.2" | 13.1" | 9 | 25 | 8° – 28° |
| March | 41° | 19° | 2.8" | 13.5" | 10 | 19 | 22° – 40° |
| April | 55° | 30° | 3.1" | 1.9" | 11 | 2 | 37° – 47° |
| May | 68° | 42° | 3.4" | 0.0" | 12 | 0 | 48° – 61° |
| June | 76° | 51° | 4.2" | 0.0" | 12 | 0 | 61° – 67° |
| July | 81° | 56° | 4.5" | 0.0" | 13 | 0 | 63° – 73° |
| August | 79° | 54° | 4.1" | 0.0" | 11 | 0 | 64° – 70° |
| September | 71° | 47° | 3.4" | 0.0" | 11 | 0 | 55° – 64° |
| October | 58° | 36° | 4.3" | 0.1" | 12 | 0 | 42° – 55° |
| November | 45° | 27° | 2.9" | 2.2" | 10 | 3 | 31° – 42° |
| December | 34° | 16° | 3.3" | 13.4" | 11 | 18 | 18° – 36° |
| Year | 56° | 33° | 40.9" | 60.6" | 132 | 95 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 8° to 28°. August is the most reliable, staying within 6°.
Where Thetford’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 Thetford’s center.
- Snow: Hanover, NH.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Union Village Dam, VT, 3 miles from the town’s center, 370 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 Thetford’s climate
What is the weather like in Thetford?
A typical July afternoon reaches 81°, a January night drops to 9°, and about 61 inches of snow falls in a normal winter. Colder January nights than 95% of U.S. towns; cooler July afternoons than 90% of U.S. towns.
How cold does it get in Thetford in winter?
January nights average 9°. About 178 nights a year reach 32° or below and 25 reach 0° or below. In the coldest January of the last 30 years the month averaged 7°.
How much snow does Thetford get?
About 61 inches in a normal winter at Hanover, NH, most of it in January, with snow on the ground about 95 days a year.
How hot does it get in Thetford?
July, with a typical high of 81° and a low of 56°. About 9 days a year reach 90° (Union Village Dam, VT).
When is the first and last frost in Thetford?
In half of years the last spring frost (32°) comes by May 9 and the first fall frost by October 2, about 145 frost-free days, at Union Village Dam, VT.
What growing zone is Thetford in?
Zone 5a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −18°.
What is the best time of year to visit Thetford?
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 Thetford getting warmer?
Yes: 1991–2020 averaged 1.8° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 79% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Thetford.
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.