| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 3.2° | -5.8° | 86mm | 11.6 | 11 |
| February | 5.1° | -5.1° | 73.8mm | 10.1 | 21 |
| March | 10.4° | -1° | 88.4mm | 10.4 | 44 |
| April | 17° | 4.2° | 97.1mm | 11.8 | 67 |
| May | 22.5° | 9.9° | 93.6mm | 12.4 | 75 |
| June | 27.1° | 15.1° | 110.8mm | 11.4 | 77 |
| July | 29.8° | 17.8° | 132.4mm | 10.9 | 67 |
| August | 28.7° | 16.9° | 118.7mm | 10.4 | 72 |
| September | 24.8° | 12.6° | 122.8mm | 9.5 | 81 |
| October | 18.4° | 6.5° | 104.8mm | 10.1 | 75 |
| November | 11.6° | 0.6° | 77.9mm | 8.6 | 54 |
| December | 5.8° | -3.2° | 100.9mm | 11.8 | 23 |
January in Allentown averages a daily high of 3.2°C with nights around -5.8°C. Expect roughly 11.6 wet days totalling 86mm. A hard month to visit for comfort alone.
February in Allentown averages a daily high of 5.1°C with nights around -5.1°C. Expect roughly 10.1 wet days totalling 73.8mm. A hard month to visit for comfort alone.
March in Allentown averages a daily high of 10.4°C with nights around -1°C. Expect roughly 10.4 wet days totalling 88.4mm. Demanding conditions — pack for it and plan indoor options.
April in Allentown averages a daily high of 17°C with nights around 4.2°C. Expect roughly 11.8 wet days totalling 97.1mm. Generally workable, with some weather to plan around.
May in Allentown averages a daily high of 22.5°C with nights around 9.9°C. Expect roughly 12.4 wet days totalling 93.6mm. Comfortable conditions for being outdoors all day.
June in Allentown averages a daily high of 27.1°C with nights around 15.1°C. Expect roughly 11.4 wet days totalling 110.8mm. Comfortable conditions for being outdoors all day.
July in Allentown averages a daily high of 29.8°C with nights around 17.8°C. Expect roughly 10.9 wet days totalling 132.4mm. Generally workable, with some weather to plan around.
August in Allentown averages a daily high of 28.7°C with nights around 16.9°C. Expect roughly 10.4 wet days totalling 118.7mm. Generally workable, with some weather to plan around.
September in Allentown averages a daily high of 24.8°C with nights around 12.6°C. Expect roughly 9.5 wet days totalling 122.8mm. Comfortable conditions for being outdoors all day.
October in Allentown averages a daily high of 18.4°C with nights around 6.5°C. Expect roughly 10.1 wet days totalling 104.8mm. Comfortable conditions for being outdoors all day.
November in Allentown averages a daily high of 11.6°C with nights around 0.6°C. Expect roughly 8.6 wet days totalling 77.9mm. Demanding conditions — pack for it and plan indoor options.
December in Allentown averages a daily high of 5.8°C with nights around -3.2°C. Expect roughly 11.8 wet days totalling 100.9mm. A hard month to visit for comfort alone.
Each month scores out of 100. It starts at 100 and loses points for daytime highs outside a 20–27°C band, for wet days, and for nights below 2°C. Nothing else is weighted in — no crowd data, no prices, no opinion. Allentown peaks at 81.
Based on 30 years of records, May–June scores highest for comfort in Allentown, balancing daytime temperature against rainfall.
July is the warmest, averaging a daily high of 29.8°C.
July is the wettest, averaging 132.4mm of rain across roughly 10.9 wet days.
January is the coolest month, with average daily highs around 3.2°C.