State guides · Pennsylvania · Climate by town
Norristown, PA rainfall, snowfall and frost dates
Thirty-year averages for Norristown from NOAA’s 1991–2020 U.S. Climate Normals: rain and snow by month, the last and first freeze, the growing season, and a frost check for any date.
Norristown averages 50.65 in. of precipitation and 25.3 in. of snow a year. The median last spring freeze (32°F) is April 8 and the median first fall freeze is Oct. 31, a growing season of about 203 days. From NOAA’s Norristown station; checked Nov. 13, 2026.
Is it safe to plant in Norristown yet?
Dates from January through July check the last spring freeze. Dates from August on check the first fall freeze.
From NOAA’s freeze probabilities for this station. Low spots and valleys can freeze later in spring and earlier in fall than the station.
Norristown frost dates
| 32°F freeze | 9 in 10 years | 1 in 2 years | 1 in 10 years |
|---|---|---|---|
| Last spring freeze comes after | March 28 | April 8 | April 23 |
| First fall freeze comes before | Nov. 12 | Oct. 31 | Oct. 14 |
Hard freeze (28°F): the median last one in spring is March 31 and the median first one in fall is Nov. 10. The growing season between the median 32°F freezes, April 8 to Oct. 31, runs about 203 days.
Planting tender plants after April 23 means a freeze afterward in only about 1 year in 10. Planting on April 8 leaves even odds. For lawn seeding windows, see our Pennsylvania grass seed guide.
Norristown rain and snow by month
| Month | Precipitation (in.) | Snow (in.) | Avg high (°F) | Avg low (°F) |
|---|---|---|---|---|
| January | 3.66 | 6.8 | 41.7 | 22.6 |
| February | 2.98 | 10.9 | 43.5 | 24.7 |
| March | 4.41 | 3.0 | 52.1 | 31.6 |
| April | 3.90 | 0.2 | 64.8 | 41.5 |
| May | 4.25 | 0.0 | 74.8 | 52.1 |
| June | 4.20 | 0.0 | 84.0 | 62.0 |
| July | 4.70 | 0.0 | 88.8 | 66.6 |
| August | 4.98 | 0.0 | 86.5 | 65.2 |
| September | 4.91 | 0.0 | 80.0 | 57.6 |
| October | 4.32 | 0.1 | 68.4 | 44.6 |
| November | 3.61 | 0.1 | 56.8 | 35.1 |
| December | 4.73 | 4.2 | 46.3 | 28.3 |
| Year | 50.65 | 25.3 | Average 55.0°F | |
Precipitation is rain plus the water in melted snow and ice. Snow is the depth of new snowfall. Monthly figures are NOAA’s normals and may not add exactly to the yearly totals because of rounding.
- Wettest month: August, 4.98 in. Driest: February, 2.98 in.
- Snowiest month: February, 10.9 in. Months averaging 1 in. or more: December through March. December through February bring about 87% of the year’s snow.
- Average lows at or below 32°F: December through March.
- Coldest nights: January, average low 22.6°F. Warmest days: July, average high 88.8°F.
Planning outdoor work in Norristown
Average lows sit at or below freezing from December through March, so plan base work, planting and seeding around the frost dates above. Frost depth and ground snow load for footings and roofs are set by your town; our design criteria by ZIP tool shows who sets them for your address. For planting beds, start with a soil test.
Towns near Norristown
| Town | Miles | Precip. (in.) | Snow (in.) | Median last freeze | Median first freeze |
|---|---|---|---|---|---|
| Sellersville | 17 | 51.68 | 21.7 | April 26 | Oct. 17 |
| Philadelphia | 18 | 44.11 | 23.1 | April 2 | Nov. 10 |
| West Chester | 18 | 50.93 | 30.5 | April 26 | Oct. 18 |
| Coatesville | 29 | 52.12 | 31.9 | April 19 | Oct. 25 |
| Allentown | 38 | 47.36 | 33.1 | April 20 | Oct. 24 |
| New Holland | 39 | 46.84 | 33.5 | April 14 | Nov. 1 |
Miles are straight-line distances between NOAA stations. See every town on our Pennsylvania rainfall and snowfall by town chart.
Questions
How much snow does Norristown, PA get a year?
Norristown averages 25.3 in. of snow a year, per NOAA’s 1991–2020 normals for its Norristown station. The snowiest month is February, at 10.9 in.
How much rain does Norristown, PA get a year?
Norristown averages 50.65 in. of precipitation a year, counting rain and melted snow. The wettest month is August, at 4.98 in.
When is the last frost in Norristown, PA?
The median last 32°F freeze in Norristown is April 8. In 1 year in 10 it comes after April 23, and in 9 years in 10 after March 28.
When is the first frost in Norristown, PA?
The median first 32°F freeze in Norristown is Oct. 31. In 1 year in 10 it comes before Oct. 14, and in 9 years in 10 before Nov. 12.
How long is the growing season in Norristown?
About 203 days between the median last and first 32°F freezes, April 8 to Oct. 31.
What is the coldest month in Norristown?
January, with an average low of 22.6°F and an average high of 41.7°F.
About this data
Station: NOAA’s Norristown station (GHCN USC00366370), elevation 62 ft, 40.110° N, 75.337° W. These are NOAA’s 1991–2020 U.S. Climate Normals, 30-year averages that NOAA recomputes every 10 years. NOAA rates this station’s precipitation normals representative, its snow normals provisional and its temperature and freeze normals representative. Representative means at least 10 years of data, with missing months filled from nearby stations. Provisional means at least 10 years of data, with gaps NOAA could not fill from nearby stations.
Your yard can differ from the station. Elevation, valleys and hillsides change how much snow falls and when the first and last freezes come.
Sources: NOAA NCEI, U.S. Climate Normals; annual and seasonal normals for USC00366370; monthly normals for USC00366370; NOAA normals file documentation. Checked Nov. 13, 2026.
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See landscape designAll Pennsylvania townsAlso: Pennsylvania grass seed guide, soil testing, design criteria by ZIP.
Muthler Landscaping & Construction LLC · 913 Bellefonte Ave, Lock Haven, PA 17745 · (570) 397-9800 · PA HIC #PA212584. Climate data from NOAA; not a forecast.
Using this guide? Link to it or cite it. It's free to use with a link back, and we keep it updated against official sources.
Cite as: Muthler Landscaping & Construction, “Norristown, PA Rainfall, Snowfall and Frost Dates,” https://muthlerlandscaping.com/state-guides/pennsylvania/climate/norristown/ (last checked November 13, 2026).
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