Upper Allen, PA climate
Upper Allen has chilly winters and warm summers. A typical July afternoon reaches 86°, a January night drops to 22°, and about 30 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Upper Allen feels like
Winter
Spring
Summer
Fall
Upper Allen 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 | 38° | 22° | 3.0" | 9.1" | 11 | 9 | 20° – 38° |
| February | 41° | 24° | 2.6" | 9.4" | 10 | 9 | 21° – 41° |
| March | 51° | 31° | 3.6" | 5.6" | 11 | 4 | 35° – 51° |
| April | 63° | 41° | 3.7" | 0.4" | 11 | 0 | 48° – 57° |
| May | 73° | 51° | 3.8" | 0 | 13 | 0 | 57° – 68° |
| June | 81° | 60° | 4.0" | 0 | 12 | 0 | 67° – 74° |
| July | 86° | 65° | 4.2" | 0 | 11 | 0 | 71° – 80° |
| August | 84° | 63° | 3.9" | 0 | 10 | 0 | 69° – 77° |
| September | 77° | 56° | 4.4" | 0 | 9 | 0 | 63° – 71° |
| October | 65° | 44° | 3.8" | 0.2" | 9 | 0 | 50° – 61° |
| November | 53° | 35° | 3.2" | 0.8" | 9 | 0 | 38° – 49° |
| December | 43° | 27° | 3.4" | 4.4" | 10 | 4 | 26° – 45° |
| Year | 63° | 43° | 43.8" | 29.9" | 126 | 26 |
“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 Allen
Upper Allen gets 44 inches of rain and melted snow a year. September is the wettest month and February the driest. Rain or snow falls on about 126 days a year. Snow covers the ground about 26 days of the year.
About 206 frost-free days a year
In half of years the last 32° night comes by April 9 and the first one by November 2. That leaves about 206 frost-free days for gardens, longer than 76% of U.S. towns.
Heating and cooling a home in Upper Allen
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Upper Allen, 81% of that work is heating and 19% 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.
Upper Allen and its neighbors
Upper Allen borders 6 towns with climate data. January nights across them vary by 0.4°. Carroll has the coldest January nights (22°) and Mechanicsburg the hottest July afternoons (86°). Upper Allen’s January low is 22° and its July high 86°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How Upper Allen 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 Allen averaged 1.8° warmer than the 1900s. The biggest change is in December (+3.2°). The shift is larger than in 87% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Upper Allen’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 21° to 41°. June is the most reliable, staying within 7°.
Common questions about Upper Allen’s climate
What is the coldest month in Upper Allen?
January, with a typical high of 38° and a low of 22°.
What is the hottest month in Upper Allen?
July, with a typical high of 86° and a low of 65°. About 22 days a year reach 90°.
How much snow does Upper Allen get?
About 30 inches in a normal winter, most of it in February.
When is the first frost in Upper Allen?
In half of years the first 32° night comes by November 2, and the last spring frost by April 9.
What is the rainiest month in Upper Allen?
September, with 4.4 inches of rain and melted snow. The year totals 44 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Upper Allen itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Middletown Harrisburg Intl Airport, PA (12 mi) away. Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.