Upper Merion, PA climate
Upper Merion has chilly winters and warm summers, with plenty of rain. A typical July afternoon reaches 87°, a January night drops to 23°, and about 8 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Upper Merion feels like
Winter
Spring
Summer
Fall
Upper Merion 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° | 3.4" | 2.7" | 9 | 3 | 24° – 40° |
| February | 43° | 25° | 2.8" | 2.4" | 9 | 3 | 23° – 41° |
| March | 51° | 32° | 4.1" | 0.6" | 10 | 2 | 36° – 50° |
| April | 64° | 41° | 3.7" | 0.1" | 11 | 0 | 48° – 58° |
| May | 74° | 51° | 4.0" | 0 | 11 | 0 | 58° – 69° |
| June | 82° | 61° | 4.4" | 0 | 9 | 0 | 69° – 76° |
| July | 87° | 66° | 4.7" | 0 | 9 | 0 | 73° – 81° |
| August | 85° | 64° | 4.6" | 0 | 9 | 0 | 70° – 79° |
| September | 78° | 57° | 4.5" | 0 | 8 | 0 | 65° – 71° |
| October | 66° | 45° | 4.1" | 0 | 9 | 0 | 51° – 63° |
| November | 55° | 36° | 3.3" | 0.2" | 8 | 0 | 39° – 50° |
| December | 45° | 28° | 4.3" | 1.6" | 10 | 1 | 29° – 49° |
| Year | 64° | 44° | 47.8" | 7.6" | 111 | 9 |
“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 Upper Merion
Upper Merion gets 48 inches of rain and melted snow a year. July is the wettest month and February the driest. Rain or snow falls on about 111 days a year. Snow covers the ground about 9 days of the year.
About 203 frost-free days a year
In half of years the last 32° night comes by April 8 and the first one by October 31. That leaves about 203 frost-free days for gardens, longer than 74% of U.S. towns.
Heating and cooling a home in Upper Merion
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Upper Merion, 80% of that work is heating and 20% is cooling.
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.
Upper Merion and its neighbors
Upper Merion borders 10 towns with climate data. January nights across them vary by 1.4°. West Norriton has the coldest January nights (23°) and Schuylkill the hottest July afternoons (88°). Upper Merion’s January low is 23° and its July high 87°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How Upper Merion 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 Upper Merion averaged 2.0° warmer than the 1900s. The biggest change is in December (+3.6°). The shift is larger than in 94% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Upper Merion’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 29° to 49°. September is the most reliable, staying within 7°.
Common questions about Upper Merion’s climate
What is the coldest month in Upper Merion?
January, with a typical high of 40° and a low of 23°.
What is the hottest month in Upper Merion?
July, with a typical high of 87° and a low of 66°. About 39 days a year reach 90°.
How much snow does Upper Merion get?
About 8 inches in a normal winter, most of it in January.
When is the first frost in Upper Merion?
In half of years the first 32° night comes by October 31, and the last spring frost by April 8.
What is the rainiest month in Upper Merion?
July, with 4.7 inches of rain and melted snow. The year totals 48 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Upper Merion itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Conshohocken, PA (3 mi, snow) and Norristown, PA (3 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.