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Allentown Weather by Month
Average temperatures, rainfall and humidity for Allentown, United States, month by month, built from OpenWeather's historical records. Use it to see what a typical Allentown month looks like before you travel — then check the live Allentown forecast for the days ahead.
Warmest month
July
29°C average high
Coolest month
January
-4°C average low
Wettest month
June
102 mm of rain
Driest month
February
42 mm of rain
Average temperature and rainfall in Allentown by month
Averages of the daily highs and lows recorded in each month, with total rainfall, mean humidity and mean wind speed.
| Month | Avg high | Avg low | Record low / high | Rainfall | Humidity | Wind |
|---|---|---|---|---|---|---|
| January | 3°C | -4°C | -19°C / 18°C | 47 mm | 70% | 11 km/h |
| February | 5°C | -3°C | -21°C / 26°C | 42 mm | 69% | 11 km/h |
| March | 10°C | 0°C | -16°C / 27°C | 55 mm | 63% | 13 km/h |
| April | 17°C | 6°C | -6°C / 31°C | 78 mm | 62% | 13 km/h |
| May | 22°C | 11°C | -1°C / 34°C | 95 mm | 69% | 10 km/h |
| June | 27°C | 16°C | 6°C / 37°C | 102 mm | 71% | 9 km/h |
| July | 29°C | 19°C | 11°C / 38°C | 99 mm | 75% | 8 km/h |
| August | 28°C | 18°C | 8°C / 35°C | 94 mm | 75% | 8 km/h |
| September | 24°C | 14°C | 2°C / 33°C | 84 mm | 76% | 9 km/h |
| October | 18°C | 9°C | -3°C / 32°C | 78 mm | 75% | 9 km/h |
| November | 11°C | 2°C | -11°C / 26°C | 52 mm | 70% | 10 km/h |
| December | 6°C | -1°C | -16°C / 20°C | 66 mm | 75% | 10 km/h |
Best time to visit Allentown
The most comfortable time to visit Allentown is generally May to June and September, balancing mild daytime temperatures against the driest stretch of the year. The city has strongly marked seasons and rain concentrates around June, totalling about 892 mm a year.
Travellers who prefer heat should aim for July, when highs average 29°C. June is the month to avoid if rain would spoil your plans — it averages 102 mm, roughly 2× the rainfall of February.
Source: OpenWeather historical and statistical weather data. Values are long-term averages, not a forecast — see the Allentown forecast for what is happening now.