Allentown, PA climate
Allentown has chilly, snowy winters and warm summers, with plenty of rain. A typical July afternoon reaches 87°, a January night drops to 20°, and about 33 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Allentown feels like
Winter
Spring
Summer
Fall
Allentown 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 | 39° | 20° | 3.4" | 9.8" | 11 | 9 | 20° – 37° |
| February | 42° | 22° | 2.7" | 10.8" | 10 | 11 | 20° – 39° |
| March | 51° | 29° | 3.8" | 6.3" | 11 | 6 | 34° – 49° |
| April | 64° | 39° | 3.8" | 0.5" | 12 | 0 | 47° – 57° |
| May | 74° | 49° | 3.8" | 0 | 12 | 0 | 57° – 67° |
| June | 82° | 58° | 4.4" | 0 | 11 | 0 | 67° – 73° |
| July | 87° | 63° | 4.9" | 0 | 11 | 0 | 70° – 79° |
| August | 84° | 61° | 4.6" | 0 | 10 | 0 | 69° – 77° |
| September | 77° | 54° | 4.7" | 0 | 10 | 0 | 62° – 70° |
| October | 66° | 42° | 4.2" | 0.2" | 10 | 0 | 49° – 61° |
| November | 54° | 33° | 3.4" | 0.9" | 9 | 1 | 38° – 48° |
| December | 44° | 26° | 3.9" | 4.6" | 12 | 5 | 27° – 46° |
| Year | 64° | 41° | 47.6" | 33.1" | 129 | 31 |
“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 Allentown
Allentown 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 129 days a year. Snow covers the ground about 31 days of the year.
About 184 frost-free days a year
In half of years the last 32° night comes by April 20 and the first one by October 24. That leaves about 184 frost-free days for gardens, longer than 57% of U.S. towns.
Heating and cooling a home in Allentown
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Allentown, 84% of that work is heating and 16% 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.
Allentown and its neighbors
Allentown borders 6 towns with climate data. January nights across them vary by 0.3°. Whitehall has the coldest January nights (20°) and South Whitehall the hottest July afternoons (87°). Allentown’s January low is 20° and its July high 87°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How Allentown 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 Allentown averaged 2.1° warmer than the 1900s. The biggest change is in December (+3.7°). The shift is larger than in 95% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Allentown’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 27° to 46°. June is the most reliable, staying within 6°.
Common questions about Allentown’s climate
What is the coldest month in Allentown?
January, with a typical high of 39° and a low of 20°.
What is the hottest month in Allentown?
July, with a typical high of 87° and a low of 63°. About 18 days a year reach 90°.
How much snow does Allentown get?
About 33 inches in a normal winter, most of it in February.
When is the first frost in Allentown?
In half of years the first 32° night comes by October 24, and the last spring frost by April 20.
What is the rainiest month in Allentown?
July, with 4.9 inches of rain and melted snow. The year totals 48 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Allentown itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Allentown Intl Airport, PA (4 mi) away. Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.