West St. Clair, PA climate
West St. Clair has chilly, snowy winters and pleasant summers. A typical July afternoon reaches 83°, a January night drops to 19°, and about 74 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in West St. Clair feels like
Winter
Spring
Summer
Fall
West St. Clair 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 | 36° | 19° | 2.9" | 23.6" | 17 | 23 | 19° – 36° |
| February | 39° | 21° | 2.5" | 17.5" | 13 | 21 | 18° – 38° |
| March | 48° | 27° | 3.4" | 9.6" | 13 | 12 | 31° – 49° |
| April | 61° | 37° | 3.6" | 2.6" | 12 | 2 | 44° – 54° |
| May | 71° | 46° | 4.1" | 0 | 13 | 0 | 53° – 66° |
| June | 79° | 55° | 4.0" | 0 | 13 | 0 | 63° – 70° |
| July | 83° | 59° | 3.9" | 0 | 11 | 0 | 67° – 75° |
| August | 81° | 58° | 3.6" | 0 | 10 | 0 | 65° – 73° |
| September | 74° | 51° | 3.8" | 0 | 10 | 0 | 60° – 67° |
| October | 63° | 40° | 3.2" | 1.2" | 11 | 1 | 48° – 57° |
| November | 50° | 31° | 2.9" | 4.8" | 10 | 4 | 35° – 46° |
| December | 40° | 24° | 3.1" | 14.8" | 14 | 16 | 21° – 42° |
| Year | 60° | 39° | 41.0" | 74.1" | 147 | 79 |
“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 West St. Clair
West St. Clair gets 41 inches of rain and melted snow a year. May is the wettest month and February the driest. Rain or snow falls on about 147 days a year. Snow covers the ground about 79 days of the year.
About 158 frost-free days a year
In half of years the last 32° night comes by May 4 and the first one by October 10. That leaves about 158 frost-free days for gardens, shorter than 73% of U.S. towns.
Heating and cooling a home in West St. Clair
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In West St. Clair, 91% of that work is heating and 9% 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.
West St. Clair and its neighbors
West St. Clair borders 4 towns with climate data. January nights across them vary by 4.0°. Ogle has the coldest January nights (16°) and East St. Clair the hottest July afternoons (85°). West St. Clair’s January low is 19° and its July high 83°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How West St. Clair 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 West St. Clair averaged 1.0° warmer than the 1900s. The biggest change is in February (+2.1°). The shift is smaller than in 67% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at West St. Clair’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 21° to 42°. June is the most reliable, staying within 7°.
Common questions about West St. Clair’s climate
What is the coldest month in West St. Clair?
January, with a typical high of 36° and a low of 19°.
What is the hottest month in West St. Clair?
July, with a typical high of 83° and a low of 59°. About 10 days a year reach 90°.
How much snow does West St. Clair get?
About 74 inches in a normal winter, most of it in January.
When is the first frost in West St. Clair?
In half of years the first 32° night comes by October 10, and the last spring frost by May 4.
What is the rainiest month in West St. Clair?
May, with 4.1 inches of rain and melted snow. The year totals 41 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for West St. Clair itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Dunlo, PA (9 mi, snow) and Shawnee Sp, PA (10 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.