Thornton, NH climate
Thornton has cold, snowy winters and pleasant summers. A typical July afternoon reaches 80°, a January night drops to 8°, and about 68 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Thornton feels like
Winter
Spring
Summer
Fall
Thornton 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 | 30-yr range |
|---|---|---|---|---|---|---|
| January | 28° | 8° | 3.4" | 18.0" | 13 | 7° – 26° |
| February | 32° | 9° | 2.7" | 15.7" | 9 | 8° – 27° |
| March | 41° | 18° | 3.2" | 13.5" | 11 | 21° – 38° |
| April | 54° | 29° | 3.6" | 3.4" | 10 | 37° – 46° |
| May | 67° | 40° | 3.9" | 0 | 14 | 48° – 59° |
| June | 75° | 50° | 4.4" | 0 | 13 | 60° – 67° |
| July | 80° | 55° | 5.0" | 0 | 13 | 62° – 70° |
| August | 78° | 53° | 4.2" | 0 | 12 | 63° – 69° |
| September | 71° | 45° | 3.9" | 0 | 12 | 53° – 62° |
| October | 57° | 35° | 4.9" | 0.3" | 12 | 42° – 53° |
| November | 45° | 26° | 3.8" | 3.2" | 12 | 30° – 41° |
| December | 34° | 16° | 4.3" | 14.2" | 12 | 18° – 34° |
| Year | 55° | 32° | 47.3" | 68.3" | 141 |
“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 Thornton
Thornton gets 47 inches of rain and melted snow a year. July is the wettest month and February the driest. Rain or snow falls on about 141 days a year.
About 149 frost-free days a year
In half of years the last 32° night comes by May 7 and the first one by October 4. That leaves about 149 frost-free days for gardens, shorter than 82% of U.S. towns.
Heating and cooling a home in Thornton
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Thornton, 96% of that work is heating and 4% 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.
Thornton and its neighbors
Thornton borders 3 towns with climate data. January nights across them vary by 3.1°. Waterville Valley has the coldest January nights (5°) and Campton the hottest July afternoons (81°). Thornton’s January low is 8° and its July high 80°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How Thornton 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 Thornton averaged 1.5° warmer than the 1900s. The biggest change is in December (+3.4°). The shift is larger than in 67% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Thornton’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. February swings the most: between 1991 and 2020 its average temperature ranged from 8° to 27°. August is the most reliable, staying within 6°.
Common questions about Thornton’s climate
What is the coldest month in Thornton?
January, with a typical high of 28° and a low of 8°.
What is the hottest month in Thornton?
July, with a typical high of 80° and a low of 55°. About 7 days a year reach 90°.
How much snow does Thornton get?
About 68 inches in a normal winter, most of it in January.
When is the first frost in Thornton?
In half of years the first 32° night comes by October 4, and the last spring frost by May 7.
What is the rainiest month in Thornton?
July, with 5.0 inches of rain and melted snow. The year totals 47 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Thornton itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Plymouth, NH (11 mi, snow) and Lincoln Nepp, NH (7 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.