Allentown weather in May: Allentown, Pennsylvania: normal highs, lows, rain and records for May
Allentown in May has a normal high of 74°F and a normal low of 51°F, a daily mean of 62°F, rising from 69°F on the 1st to 77°F by the 31st. Measurable precipitation falls on 12 days in a normal May, 3.65 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 23°C and low of 10°C, 93 mm of precipitation in May.
- NOAA stationAllentown Lehigh Valley International Airport
- Station IDUSW00014737
- Location40.65°N 75.45°W
- Elevation390 ft (119 m)
- From the center4 miles
- Population127,138
- Jan 38° 22°
- Feb 42° 23°
- Mar 51° 31°
- Apr 63° 40°
- May 74° 51°
- Jun 82° 60°
- Jul 86° 65°
- Aug 84° 63°
- Sep 77° 55°
- Oct 66° 44°
- Nov 54° 34°
- Dec 43° 27°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Allentown in May?
The normal high is 74°F and the normal low 51°F, for a daily mean of 62.0°F. May is 10.2°F warmer than April and 8.9°F cooler than June. May is the 5th warmest month of the year in Allentown and the 8th wettest. Across the month the normal high rises 8°F, from 69°F on May 1 to 77°F on May 31. From one year to the next May's mean temperature typically moves about 3.2°F either way (NOAA's standard deviation), so roughly two Mays in three average between 59°F and 65°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 40%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| May 1 | 69°F | 46°F | 39% | 24% |
| May 8 | 72°F | 48°F | 39% | 24% |
| May 15 | 73°F | 50°F | 40% | 24% |
| May 22 | 75°F | 53°F | 40% | 25% |
| May 31 | 77°F | 55°F | 40% | 25% |
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 | 69°F | 46°F | 39% | 24% | 13 h 50 min |
| May 2 | 70°F | 46°F | 39% | 24% | 14 h |
| May 3 | 70°F | 46°F | 39% | 24% | 14 h |
| May 4 | 70°F | 47°F | 39% | 24% | 14 h |
| May 5 | 71°F | 47°F | 39% | 24% | 14 h |
| May 6 | 71°F | 47°F | 39% | 24% | 14 h 10 min |
| May 7 | 71°F | 48°F | 39% | 24% | 14 h 10 min |
| May 8 | 72°F | 48°F | 39% | 24% | 14 h 10 min |
| May 9 | 72°F | 48°F | 39% | 24% | 14 h 10 min |
| May 10 | 72°F | 49°F | 39% | 24% | 14 h 10 min |
| May 11 | 72°F | 49°F | 39% | 24% | 14 h 20 min |
| May 12 | 73°F | 49°F | 39% | 24% | 14 h 20 min |
| May 13 | 73°F | 50°F | 39% | 24% | 14 h 20 min |
| May 14 | 73°F | 50°F | 40% | 24% | 14 h 20 min |
| May 15 | 73°F | 50°F | 40% | 24% | 14 h 20 min |
| May 16 | 74°F | 51°F | 40% | 24% | 14 h 30 min |
| May 17 | 74°F | 51°F | 40% | 25% | 14 h 30 min |
| May 18 | 74°F | 51°F | 40% | 25% | 14 h 30 min |
| May 19 | 74°F | 52°F | 40% | 25% | 14 h 30 min |
| May 20 | 75°F | 52°F | 40% | 25% | 14 h 30 min |
| May 21 | 75°F | 52°F | 40% | 25% | 14 h 40 min |
| May 22 | 75°F | 53°F | 40% | 25% | 14 h 40 min |
| May 23 | 75°F | 53°F | 40% | 25% | 14 h 40 min |
| May 24 | 76°F | 53°F | 40% | 25% | 14 h 40 min |
| May 25 | 76°F | 54°F | 40% | 25% | 14 h 40 min |
| May 26 | 76°F | 54°F | 40% | 25% | 14 h 40 min |
| May 27 | 76°F | 54°F | 40% | 25% | 14 h 50 min |
| May 28 | 77°F | 54°F | 40% | 25% | 14 h 50 min |
| May 29 | 77°F | 55°F | 40% | 25% | 14 h 50 min |
| May 30 | 77°F | 55°F | 40% | 25% | 14 h 50 min |
| May 31 | 77°F | 55°F | 40% | 25% | 14 h 50 min |
- Normal high
- 74°FMay average
- Normal low
- 51°FMay average
- Precipitation
- 3.65 inmonth total
- Days with precipitation
- 120.01 inch or more
- Days at 90°F or more
- 1
- Daylight
- 13 h 50 min to 14 h 50 minMay 1 to May 31
- Days at 70°F or more
- 19
- Days at 80°F or more
- 8
- Sunshine
- 69%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00014737; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Allentown in May?
On a given May day the chance of 0.01 inch or more is 40% on average, highest around May 23 (40%). In all, 3.65 in falls on 12 days of a normal May, 1 of them with an inch or more.
In a normal May in Allentown, 1 days reach 90°F.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00014737.
How humid and windy is Allentown in May?
At 3 p.m. the normal temperature is 75°F with 49% relative humidity and a dew point of 54°F; at 6 a.m. it is 59°F with 83% humidity. The wind averages 6.8 mph, most often from the west-southwest in the afternoon.
| Time | Temperature | Dew point | Humidity | Wind | Clear or few clouds |
|---|---|---|---|---|---|
| 6 a.m. | 59°F | 54°F | 83% | 4.5 mph | 53% |
| 9 a.m. | 67°F | 55°F | 64% | 7.3 mph | 55% |
| noon | 73°F | 55°F | 53% | 9.0 mph | 51% |
| 3 p.m. | 75°F | 54°F | 49% | 9.8 mph | 44% |
| 6 p.m. | 72°F | 54°F | 52% | 9.1 mph | 54% |
| 9 p.m. | 66°F | 54°F | 67% | 6.2 mph | 60% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00014737. Hourly normals exist only for NOAA's first-order stations; a dash where NOAA publishes no value for that hour (the sky at some hours).
What are the records for May in Allentown?
The warmest May temperature on Allentown's official record (since 1922) is 97°F, on May 19, 1962; the coldest is 28°F, on May 10, 1947. The wettest May brought 10.62 in (1984).
The May mean against the 1991-2020 normal of 62.0°F: 2021 60.3°F (−1.7), 2022 62.8°F (+0.8), 2023 58.6°F (−3.4), 2024 63.4°F (+1.4), 2025 60.8°F (−1.2), 2026 60.5°F (−1.5). 2 of 6 ran warmer than normal.
| May | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 60.3°F | −1.7°F | 3.56 in |
| 2022 | 62.8°F | +0.8°F | 5.27 in |
| 2023 | 58.6°F | −3.4°F | 0.24 in |
| 2024 | 63.4°F | +1.4°F | 3.77 in |
| 2025 | 60.8°F | −1.2°F | 10.45 in |
| 2026 | 60.5°F | −1.5°F | 2.19 in |
Source: records: ACIS, NWS threaded record ABEthr; recent months: ACIS, station USW00014737. Records and recent months use complete months only.
How does May in Allentown 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; Allentown's is 74°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.