Norristown weather in May: Norristown, Pennsylvania: normal highs, lows, rain and records for May
Norristown in May has a normal high of 75°F and a normal low of 52°F, a daily mean of 63°F, rising from 71°F on the 1st to 79°F by the 31st. Measurable precipitation falls on 14 days in a normal May, 4.25 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 24°C and low of 11°C, 108 mm of precipitation in May.
- 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 May?
The normal high is 75°F and the normal low 52°F, for a daily mean of 63.4°F. May is 10.3°F warmer than April and 9.6°F cooler than June. May is the 5th warmest month of the year in Norristown and the 7th wettest. Across the month the normal high rises 8°F, from 71°F on May 1 to 79°F on May 31. From one year to the next May's mean temperature typically moves about 3.1°F either way (NOAA's standard deviation), so roughly two Mays in three average between 60°F and 67°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 47%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| May 1 | 71°F | 47°F | 43% | 26% |
| May 8 | 73°F | 50°F | 44% | 26% |
| May 15 | 75°F | 52°F | 45% | 27% |
| May 22 | 76°F | 54°F | 47% | 29% |
| May 31 | 79°F | 57°F | 45% | 29% |
Every day of May: normal high, low and chance of precipitation (warmest afternoon May 31, coldest night May 1)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| May 1 | 71°F | 47°F | 43% | 26% | 13 h 50 min |
| May 2 | 71°F | 48°F | 43% | 26% | 13 h 50 min |
| May 3 | 71°F | 48°F | 43% | 26% | 14 h |
| May 4 | 72°F | 48°F | 43% | 26% | 14 h |
| May 5 | 72°F | 49°F | 44% | 26% | 14 h |
| May 6 | 72°F | 49°F | 44% | 26% | 14 h |
| May 7 | 72°F | 49°F | 44% | 26% | 14 h 10 min |
| May 8 | 73°F | 50°F | 44% | 26% | 14 h 10 min |
| May 9 | 73°F | 50°F | 44% | 27% | 14 h 10 min |
| May 10 | 73°F | 50°F | 44% | 27% | 14 h 10 min |
| May 11 | 74°F | 51°F | 44% | 27% | 14 h 10 min |
| May 12 | 74°F | 51°F | 45% | 27% | 14 h 20 min |
| May 13 | 74°F | 51°F | 45% | 27% | 14 h 20 min |
| May 14 | 74°F | 51°F | 45% | 27% | 14 h 20 min |
| May 15 | 75°F | 52°F | 45% | 27% | 14 h 20 min |
| May 16 | 75°F | 52°F | 45% | 28% | 14 h 20 min |
| May 17 | 75°F | 52°F | 46% | 28% | 14 h 30 min |
| May 18 | 75°F | 53°F | 46% | 28% | 14 h 30 min |
| May 19 | 76°F | 53°F | 46% | 28% | 14 h 30 min |
| May 20 | 76°F | 53°F | 46% | 28% | 14 h 30 min |
| May 21 | 76°F | 54°F | 46% | 29% | 14 h 30 min |
| May 22 | 76°F | 54°F | 47% | 29% | 14 h 30 min |
| May 23 | 77°F | 54°F | 47% | 29% | 14 h 40 min |
| May 24 | 77°F | 55°F | 47% | 29% | 14 h 40 min |
| May 25 | 77°F | 55°F | 46% | 29% | 14 h 40 min |
| May 26 | 78°F | 55°F | 46% | 29% | 14 h 40 min |
| May 27 | 78°F | 56°F | 46% | 29% | 14 h 40 min |
| May 28 | 78°F | 56°F | 46% | 29% | 14 h 40 min |
| May 29 | 78°F | 56°F | 46% | 29% | 14 h 40 min |
| May 30 | 79°F | 57°F | 46% | 29% | 14 h 50 min |
| May 31 | 79°F | 57°F | 45% | 29% | 14 h 50 min |
- Normal high
- 75°FMay average
- Normal low
- 52°FMay average
- Precipitation
- 4.25 inmonth total
- Days with precipitation
- 140.01 inch or more
- Days at 90°F or more
- 3
- Daylight
- 13 h 50 min to 14 h 50 minMay 1 to May 31
- Days at 70°F or more
- 22
- Days at 80°F or more
- 11
- Sunshine
- 69%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 May?
On a given May day the chance of 0.01 inch or more is 45% on average, highest around May 23 (47%). In all, 4.25 in falls on 14 days of a normal May, 1 of them with an inch or more.
In a normal May in Norristown, 3 days reach 90°F.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USC00366370.
What are the records for May in Norristown?
The warmest May temperature on this station's record (since 1951) is 98°F, on May 19, 1962; the coldest is 29°F, on May 10, 1966. The wettest May brought 10.23 in (2014).
The May mean against the 1991-2020 normal of 63.4°F: 2021 62.8°F (−0.6), 2022 64.0°F (+0.6), 2023 60.6°F (−2.8), 2024 64.9°F (+1.5), 2025 62.8°F (−0.6), 2026 62.3°F (−1.1). 2 of 6 ran warmer than normal.
| May | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 62.8°F | −0.6°F | 3.98 in |
| 2022 | 64.0°F | +0.6°F | 5.42 in |
| 2023 | 60.6°F | −2.8°F | 1.64 in |
| 2024 | 64.9°F | +1.5°F | 3.37 in |
| 2025 | 62.8°F | −0.6°F | 7.08 in |
| 2026 | 62.3°F | −1.1°F | 4.18 in |
Source: records: ACIS, station USC00366370; recent months: ACIS, station USC00366370. Records and recent months use complete months only.
How does May in Norristown compare across Pennsylvania?
Across the 108 places PlainClimate covers in Pennsylvania, May normal highs run from 65°F in Laporte to 75°F in Phoenixville; Norristown's is 75°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.