Norristown weather in September: Norristown, Pennsylvania: normal highs, lows, rain and records for September
Norristown in September has a normal high of 80°F and a normal low of 58°F, a daily mean of 69°F, falling from 84°F on the 1st to 75°F by the 30th. Measurable precipitation falls on 9 days in a normal September, 4.91 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 27°C and low of 14°C, 125 mm of precipitation in September.
- NOAA stationNorristown
- Station IDUSC00366370
- Location40.11°N 75.34°W
- Elevation62 ft (19 m)
- From the centerunder 1 mile
- Population36,075
- Jan 42° 23°
- Feb 44° 25°
- Mar 52° 32°
- Apr 65° 42°
- May 75° 52°
- Jun 84° 62°
- Jul 89° 67°
- Aug 87° 65°
- Sep 80° 58°
- Oct 68° 45°
- Nov 57° 35°
- Dec 46° 28°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Norristown in September?
The normal high is 80°F and the normal low 58°F, for a daily mean of 68.8°F. September is 7.1°F cooler than August and 12.3°F warmer than October. September is the 4th warmest month of the year in Norristown and the 2nd wettest. Across the month the normal high falls 9°F, from 84°F on September 1 to 75°F on September 30. From one year to the next September's mean temperature typically moves about 2.4°F either way (NOAA's standard deviation), so roughly two Septembers in three average between 66°F and 71°F.
Bars above: each day's normal high to low. Columns below: the chance of 0.01 inch or more of precipitation that day, on a scale of 0 to 100% (highest 33%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| September 1 | 84°F | 63°F | 29% | 20% |
| September 8 | 83°F | 61°F | 29% | 19% |
| September 15 | 81°F | 58°F | 29% | 19% |
| September 22 | 78°F | 55°F | 30% | 19% |
| September 30 | 75°F | 51°F | 33% | 20% |
Every day of September: normal high, low and chance of precipitation (warmest afternoon September 1, coldest night September 30)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| September 1 | 84°F | 63°F | 29% | 20% | 13 h 10 min |
| September 2 | 84°F | 63°F | 29% | 20% | 13 h |
| September 3 | 84°F | 62°F | 29% | 20% | 13 h |
| September 4 | 84°F | 62°F | 29% | 20% | 13 h |
| September 5 | 84°F | 62°F | 29% | 20% | 13 h |
| September 6 | 83°F | 61°F | 29% | 20% | 12 h 50 min |
| September 7 | 83°F | 61°F | 29% | 19% | 12 h 50 min |
| September 8 | 83°F | 61°F | 29% | 19% | 12 h 50 min |
| September 9 | 82°F | 60°F | 29% | 19% | 12 h 50 min |
| September 10 | 82°F | 60°F | 29% | 19% | 12 h 40 min |
| September 11 | 82°F | 60°F | 29% | 19% | 12 h 40 min |
| September 12 | 82°F | 59°F | 29% | 19% | 12 h 40 min |
| September 13 | 81°F | 59°F | 29% | 19% | 12 h 40 min |
| September 14 | 81°F | 59°F | 29% | 19% | 12 h 30 min |
| September 15 | 81°F | 58°F | 29% | 19% | 12 h 30 min |
| September 16 | 80°F | 58°F | 29% | 19% | 12 h 30 min |
| September 17 | 80°F | 57°F | 29% | 19% | 12 h 30 min |
| September 18 | 79°F | 57°F | 30% | 19% | 12 h 20 min |
| September 19 | 79°F | 56°F | 30% | 19% | 12 h 20 min |
| September 20 | 79°F | 56°F | 30% | 19% | 12 h 20 min |
| September 21 | 78°F | 56°F | 30% | 19% | 12 h 20 min |
| September 22 | 78°F | 55°F | 30% | 19% | 12 h 10 min |
| September 23 | 77°F | 55°F | 31% | 20% | 12 h 10 min |
| September 24 | 77°F | 54°F | 31% | 20% | 12 h 10 min |
| September 25 | 77°F | 54°F | 31% | 20% | 12 h 10 min |
| September 26 | 76°F | 53°F | 32% | 20% | 12 h |
| September 27 | 76°F | 53°F | 32% | 20% | 12 h |
| September 28 | 75°F | 52°F | 32% | 20% | 12 h |
| September 29 | 75°F | 52°F | 32% | 20% | 11 h 50 min |
| September 30 | 75°F | 51°F | 33% | 20% | 11 h 50 min |
- Normal high
- 80°FSeptember average
- Normal low
- 58°FSeptember average
- Precipitation
- 4.91 inmonth total
- Days with precipitation
- 90.01 inch or more
- Days at 90°F or more
- 4
- Daylight
- 13 h 10 min to 11 h 50 minSeptember 1 to September 30
- Days at 70°F or more
- 27
- Days at 80°F or more
- 17
- Sunshine
- 75%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USC00366370; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Norristown in September?
On a given September day the chance of 0.01 inch or more is 30% on average, highest around September 30 (33%). In all, 4.91 in falls on 9 days of a normal September, 1 of them with an inch or more.
In a normal September in Norristown, 4 days reach 90°F.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USC00366370.
What are the records for September in Norristown?
The warmest September temperature on this station's record (since 1951) is 102°F, on September 2, 1953; the coldest is 34°F, on September 18, 2014. The wettest September brought 10.52 in (2011).
The September mean against the 1991-2020 normal of 68.8°F: 2022 68.7°F (−0.1), 2023 68.9°F (+0.1), 2024 68.3°F (−0.5), 2025 69.5°F (+0.7), 2026 70.0°F (+1.2). 3 of 5 ran warmer than normal.
| September | Mean | Against normal | Precip. |
|---|---|---|---|
| 2022 | 68.7°F | −0.1°F | 4.72 in |
| 2023 | 68.9°F | +0.1°F | 5.24 in |
| 2024 | 68.3°F | −0.5°F | 1.13 in |
| 2025 | 69.5°F | +0.7°F | 3.47 in |
| 2026 | 70.0°F | +1.2°F | 6.97 in |
Source: records: ACIS, station USC00366370; recent months: ACIS, station USC00366370. Records and recent months use complete months only.
How does September in Norristown compare across Pennsylvania?
Across the 108 places PlainClimate covers in Pennsylvania, September normal highs run from 68°F in Laporte to 80°F in Marcus Hook; Norristown's is 80°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.
Other months and places
- Norristown in August87°F by day, 65°F at night
- Norristown in October68°F by day, 45°F at night
- Norristown through the yearEvery month, frost dates, records and recent years
- Pennsylvania in SeptemberThe statewide normal and the warmest and coolest places
- Marcus Hook: Pennsylvania's warmest Septembernormal high 80°F