Climate averages 1991–2020
Allentown weather
in May.
A mild, wet month: the 5th warmest and the 5th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
May is a mild month in Allentown: daytime highs average 21.3°C and nights cool to about 10.4°C. By daytime temperature it is the 5th warmest of the 12 months.
Expect about 95 mm of rain on roughly 12 days, which makes May a wet month (the 5th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 14 h 25 min on an average May day.
The nearest other city in this atlas is Bethlehem, United States (10 km away). In May its highs average 21.2°C, about as warm as Allentown, with 93 mm of rain.
Among the 498 cities listed in the United States, Allentown ranks joint 327th of 498 for the warmest May highs and joint 330th of 498 for the driest May (rainfall, lowest first). The mean May high of those 498 cities is 23.8°C; Allentown is 2.5°C cooler than that mean.
From May to June, average highs rise by 4.9°C to 26.2°C, and monthly rainfall rises from 95 mm to 103 mm.
The annual picture
May in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Allentown climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 2.8°C-5.7°C | -5.7°C | 87 | 9.5 | 9.610 h |
| February | 4.4°C-5.2°C | -5.2°C | 77 | 9.1 | 10.611 h |
| March | 9.1°C-1.3°C | -1.3°C | 103 | 11.0 | 11.912 h |
| April | 15.8°C4.5°C | 4.5°C | 99 | 10.6 | 13.313 h |
| May, selected | 21.3°C10.4°C | 10.4°C | 95 | 11.5 | 14.414 h |
| June | 26.2°C15.6°C | 15.6°C | 103 | 11.3 | 15.015 h |
| July | 29.1°C18.6°C | 18.6°C | 98 | 11.2 | 14.815 h |
| August | 28.1°C17.9°C | 17.9°C | 93 | 10.1 | 13.814 h |
| September | 24.1°C14.1°C | 14.1°C | 113 | 8.8 | 12.513 h |
| October | 17.2°C7.8°C | 7.8°C | 100 | 8.9 | 11.211 h |
| November | 10.8°C2.1°C | 2.1°C | 81 | 8.0 | 10.010 h |
| December | 5.4°C-2.4°C | -2.4°C | 101 | 9.4 | 9.39 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
May in nearby cities
- Bethlehem, United States in MayUnited States · 10 kmHigh 21.2°C · Low 10.3°C · 93 mm rain
- Reading, United States in MayUnited States · 48 kmHigh 22.0°C · Low 11.5°C · 92 mm rain
- Trenton in MayUnited States · 77 kmHigh 21.8°C · Low 11.6°C · 88 mm rain
- Philadelphia in MayUnited States · 78 kmHigh 22.4°C · Low 12.3°C · 90 mm rain
- Camden in MayUnited States · 82 kmHigh 22.3°C · Low 12.2°C · 86 mm rain
- Cherry Hill in MayUnited States · 84 kmHigh 22.1°C · Low 12.3°C · 86 mm rain
- Scranton in MayUnited States · 90 kmHigh 20.0°C · Low 10.0°C · 89 mm rain
- Edison in MayUnited States · 92 kmHigh 21.4°C · Low 11.6°C · 90 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Allentown) is explained once on the Allentown year overview and on the Sources, method and limits page.