Rosemont has chilly winters and warm summers, with plenty of rain
A typical July afternoon reaches 87°, a January night drops to 24°, and about 8 inches of snow falls in a normal winter.
A year in Rosemont at a glance
Each month’s typical high and low, and what it brings.
What stands out about Rosemont’s climate
Read from where Rosemont sits among Pennsylvania’s towns. The page puts what stands out first.
What a year in Rosemont feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
8 inches of snow, 48 of rain and melt
July is the wettest month and February the driest. Rain or snow falls on about 111 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
About 203 frost-free days a year
In half of years the last 32° night comes by April 8 and the first by October 31.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
Living with Rosemont’s climate
What the numbers mean for a garden, a driveway, a furnace and a free afternoon.
203 frost-free days. The last frost comes by Apr 8 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Oct 31.
About 8" in a normal winter.
Months averaging under 55° run from November through April. Heating is 80% of the year’s heating-and-cooling load.
About 39 days a year reach 90°, and July afternoons average 87°.
The nicest months are April, May, June, September and October. 1.4 miles of trails are waiting.
Parks & trails →Normals are averages. Ice storms, nor’easters, floods and heat waves are on the natural hazards page.
Natural hazards →Warmer than it used to be
The last 30 years in Rosemont averaged 2.1° warmer than the 1900s. The biggest change is in December (+3.6°).
A bigger shift than in 95% of U.S. towns.
Change by month
Rosemont and its neighbors
Villanova has the coldest January nights next door (24°) and Bryn Mawr the hottest July afternoons (87°). Tap a town to see its climate.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value. Snow and frost-free days come from the nearest weather station, so neighbors often share them.
How Rosemont compares
Against every U.S. town on TownTapestry, each counted once, with its place in Pennsylvania.
Rosemont 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° | 24° | 3.5" | 2.7" | 9 | 3 | 24° – 39° |
| February | 43° | 26° | 2.8" | 2.4" | 9 | 3 | 23° – 42° |
| March | 51° | 32° | 4.1" | 0.6" | 10 | 2 | 37° – 50° |
| April | 64° | 42° | 3.7" | 0.1" | 11 | 0 | 49° – 58° |
| May | 73° | 52° | 3.9" | 0 | 11 | 0 | 58° – 68° |
| June | 82° | 62° | 4.4" | 0 | 9 | 0 | 69° – 76° |
| July | 87° | 67° | 4.7" | 0 | 9 | 0 | 72° – 80° |
| August | 85° | 65° | 4.5" | 0 | 9 | 0 | 70° – 79° |
| September | 78° | 58° | 4.6" | 0 | 8 | 0 | 64° – 72° |
| October | 66° | 47° | 4.0" | 0 | 9 | 0 | 52° – 63° |
| November | 55° | 37° | 3.4" | 0.2" | 8 | 0 | 40° – 50° |
| December | 45° | 29° | 4.3" | 1.6" | 10 | 1 | 29° – 49° |
| Year | 64° | 45° | 48.0" | 7.6" | 111 | 9 |
Heating and cooling a home in Rosemont
80% of the work is heating.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. Source: NOAA station normals.
How much a month can swing
A normal is an average. December swings the most: from 1991 to 2020 its average ranged from 29° to 49°. June is the most reliable, staying within 7°.
Common questions about Rosemont’s climate
What is the coldest month in Rosemont?
January, with a typical high of 40° and a low of 24°.
What is the hottest month in Rosemont?
July, with a typical high of 87° and a low of 67°. About 39 days a year reach 90°.
How much snow does Rosemont get?
About 8 inches in a normal winter, most of it in January.
When is the first frost in Rosemont?
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 Rosemont?
July, with 4.7 inches of rain and melted snow. The year totals 48 inches.
Neighbors talk weather
Gardens, snow, and the best days of the year in Rosemont.
Your answer becomes a post in Town Square.
Temperatures and rainfall come from NOAA’s gridded climate normals for Rosemont 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 (5 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. Today’s forecast: National Weather Service.