Arnold, PA climate
Arnold has chilly winters and warm summers. A typical July afternoon reaches 85°, a January night drops to 21°, and about 25 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Arnold feels like
Winter
Spring
Summer
Fall
Arnold 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 | 37° | 21° | 3.1" | 10.2" | 15 | 14 | 21° – 39° |
| February | 41° | 23° | 2.5" | 5.6" | 14 | 9 | 18° – 40° |
| March | 50° | 30° | 3.2" | 3.0" | 12 | 3 | 34° – 51° |
| April | 64° | 39° | 3.5" | 0.2" | 13 | 0 | 46° – 56° |
| May | 73° | 49° | 3.8" | 0 | 15 | 0 | 54° – 68° |
| June | 81° | 58° | 4.5" | 0 | 14 | 0 | 65° – 72° |
| July | 85° | 62° | 4.4" | 0 | 13 | 0 | 69° – 77° |
| August | 83° | 61° | 3.6" | 0 | 12 | 0 | 68° – 76° |
| September | 77° | 54° | 3.7" | 0 | 10 | 0 | 62° – 70° |
| October | 65° | 43° | 3.1" | 0 | 13 | 0 | 50° – 60° |
| November | 52° | 34° | 3.0" | 0.7" | 11 | 1 | 37° – 48° |
| December | 42° | 27° | 3.2" | 5.3" | 14 | 7 | 24° – 45° |
| Year | 62° | 41° | 41.6" | 25.0" | 155 | 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 Arnold
Arnold gets 42 inches of rain and melted snow a year. June is the wettest month and February the driest. Rain or snow falls on about 155 days a year. Snow covers the ground about 34 days of the year.
About 199 frost-free days a year
In half of years the last 32° night comes by April 16 and the first one by November 2. That leaves about 199 frost-free days for gardens, longer than 72% of U.S. towns.
Heating and cooling a home in Arnold
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Arnold, 88% of that work is heating and 12% 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.
Arnold and its neighbors
Arnold borders 2 towns with climate data. January nights across them vary by 0.4°. East Deer has the coldest January nights (21°) and New Kensington the hottest July afternoons (85°). Arnold’s January low is 21° and its July high 85°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How Arnold 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 Arnold averaged 1.0° warmer than the 1900s. The biggest change is in December (+2.2°). The shift is smaller than in 68% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Arnold’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 18° to 40°. June is the most reliable, staying within 7°.
Common questions about Arnold’s climate
What is the coldest month in Arnold?
January, with a typical high of 37° and a low of 21°.
What is the hottest month in Arnold?
July, with a typical high of 85° and a low of 62°. About 14 days a year reach 90°.
How much snow does Arnold get?
About 25 inches in a normal winter, most of it in January.
When is the first frost in Arnold?
In half of years the first 32° night comes by November 2, and the last spring frost by April 16.
What is the rainiest month in Arnold?
June, with 4.5 inches of rain and melted snow. The year totals 42 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Arnold itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Murrysville 2 Sw, PA (12 mi, snow) and Natrona Lock 4, 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.