Thornbury, PA climate
Thornbury has chilly, snowy winters and warm summers, with plenty of rain. A typical July afternoon reaches 86°, a January night drops to 23°, and about 31 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Thornbury feels like
Winter
Spring
Summer
Fall
Thornbury 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 | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 40° | 23° | 3.5" | 7.9" | 11 | 11 | 24° – 39° |
| February | 43° | 25° | 2.8" | 13.2" | 9 | 14 | 24° – 41° |
| March | 51° | 32° | 4.2" | 4.1" | 11 | 4 | 36° – 50° |
| April | 64° | 41° | 3.7" | 0.4" | 11 | 0 | 48° – 58° |
| May | 73° | 51° | 3.8" | 0 | 11 | 0 | 57° – 68° |
| June | 82° | 61° | 4.4" | 0 | 11 | 0 | 68° – 75° |
| July | 86° | 66° | 4.6" | 0 | 10 | 0 | 72° – 80° |
| August | 84° | 64° | 4.5" | 0 | 10 | 0 | 70° – 78° |
| September | 78° | 57° | 4.8" | 0 | 9 | 0 | 64° – 71° |
| October | 66° | 45° | 4.2" | 0 | 11 | 0 | 51° – 63° |
| November | 55° | 36° | 3.4" | 0.5" | 10 | 1 | 39° – 50° |
| December | 45° | 28° | 4.1" | 4.4" | 11 | 4 | 28° – 48° |
| Year | 64° | 44° | 48.1" | 30.5" | 124 | 34 |
“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 Thornbury
Thornbury gets 48 inches of rain and melted snow a year. September is the wettest month and February the driest. Rain or snow falls on about 124 days a year. Snow covers the ground about 34 days of the year.
About 174 frost-free days a year
In half of years the last 32° night comes by April 26 and the first one by October 18. That leaves about 174 frost-free days for gardens, shorter than 56% of U.S. towns.
Heating and cooling a home in Thornbury
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Thornbury, 86% of that work is heating and 14% 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.
Thornbury and its neighbors
Thornbury borders 3 towns with climate data. January nights across them vary by 0.2°. Birmingham has both the coldest January nights (23°) and the hottest July afternoons (87°). Thornbury’s January low is 23° and its July high 86°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How Thornbury 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 Thornbury averaged 1.9° warmer than the 1900s. The biggest change is in December (+3.4°). The shift is larger than in 89% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Thornbury’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. December swings the most: between 1991 and 2020 its average temperature ranged from 28° to 48°. September is the most reliable, staying within 7°.
Common questions about Thornbury’s climate
What is the coldest month in Thornbury?
January, with a typical high of 40° and a low of 23°.
What is the hottest month in Thornbury?
July, with a typical high of 86° and a low of 66°. About 27 days a year reach 90°.
How much snow does Thornbury get?
About 31 inches in a normal winter, most of it in February.
When is the first frost in Thornbury?
In half of years the first 32° night comes by October 18, and the last spring frost by April 26.
What is the rainiest month in Thornbury?
September, with 4.8 inches of rain and melted snow. The year totals 48 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Thornbury itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at West Chester 2 Nw, PA (5 mi) away. Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.