| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | -0.5° | -9.1° | 53.5mm | 10.7 | 9 |
| February | 2.1° | -7.7° | 53.2mm | 10.3 | 10 |
| March | 7.7° | -2.7° | 69.6mm | 11.2 | 31 |
| April | 14.9° | 3.3° | 105.3mm | 11.5 | 61 |
| May | 20.7° | 8.7° | 113.7mm | 13.6 | 73 |
| June | 26.3° | 14.5° | 133.1mm | 12.4 | 75 |
| July | 28.8° | 17.1° | 110.7mm | 10 | 73 |
| August | 28.2° | 16.7° | 105.6mm | 9.9 | 75 |
| September | 24.6° | 12.3° | 91.2mm | 8.6 | 83 |
| October | 17° | 5.5° | 59mm | 11.8 | 67 |
| November | 9.9° | 0.1° | 58.1mm | 10.8 | 43 |
| December | 2.3° | -6.4° | 62.5mm | 12.2 | 8 |
January in West Allis averages a daily high of -0.5°C with nights around -9.1°C. Expect roughly 10.7 wet days totalling 53.5mm. A hard month to visit for comfort alone.
February in West Allis averages a daily high of 2.1°C with nights around -7.7°C. Expect roughly 10.3 wet days totalling 53.2mm. A hard month to visit for comfort alone.
March in West Allis averages a daily high of 7.7°C with nights around -2.7°C. Expect roughly 11.2 wet days totalling 69.6mm. A hard month to visit for comfort alone.
April in West Allis averages a daily high of 14.9°C with nights around 3.3°C. Expect roughly 11.5 wet days totalling 105.3mm. Generally workable, with some weather to plan around.
May in West Allis averages a daily high of 20.7°C with nights around 8.7°C. Expect roughly 13.6 wet days totalling 113.7mm. Generally workable, with some weather to plan around.
June in West Allis averages a daily high of 26.3°C with nights around 14.5°C. Expect roughly 12.4 wet days totalling 133.1mm. Comfortable conditions for being outdoors all day.
July in West Allis averages a daily high of 28.8°C with nights around 17.1°C. Expect roughly 10 wet days totalling 110.7mm. Generally workable, with some weather to plan around.
August in West Allis averages a daily high of 28.2°C with nights around 16.7°C. Expect roughly 9.9 wet days totalling 105.6mm. Comfortable conditions for being outdoors all day.
September in West Allis averages a daily high of 24.6°C with nights around 12.3°C. Expect roughly 8.6 wet days totalling 91.2mm. Comfortable conditions for being outdoors all day.
October in West Allis averages a daily high of 17°C with nights around 5.5°C. Expect roughly 11.8 wet days totalling 59mm. Generally workable, with some weather to plan around.
November in West Allis averages a daily high of 9.9°C with nights around 0.1°C. Expect roughly 10.8 wet days totalling 58.1mm. Demanding conditions — pack for it and plan indoor options.
December in West Allis averages a daily high of 2.3°C with nights around -6.4°C. Expect roughly 12.2 wet days totalling 62.5mm. 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. West Allis peaks at 83.
Based on 30 years of records, August–September scores highest for comfort in West Allis, balancing daytime temperature against rainfall.
July is the warmest, averaging a daily high of 28.8°C.
June is the wettest, averaging 133.1mm of rain across roughly 12.4 wet days.
January is the coolest month, with average daily highs around -0.5°C.