| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 5.7° | 0.5° | 59.7mm | 17 | 22 |
| February | 6.9° | 0.7° | 53.7mm | 13.9 | 28 |
| March | 10.5° | 2° | 49.5mm | 13 | 44 |
| April | 15.2° | 4.4° | 39.8mm | 10.4 | 64 |
| May | 18.9° | 7.6° | 62.1mm | 13 | 70 |
| June | 22.5° | 11.1° | 63.1mm | 12.4 | 75 |
| July | 24.6° | 13° | 80.9mm | 14.2 | 72 |
| August | 24.1° | 13.2° | 81mm | 14.3 | 71 |
| September | 20.6° | 10.4° | 51.4mm | 11.4 | 77 |
| October | 15.5° | 7.5° | 53.8mm | 12.1 | 61 |
| November | 10.1° | 4.1° | 58.7mm | 14.3 | 40 |
| December | 6.7° | 1.7° | 58.7mm | 16.5 | 27 |
January in Hamm averages a daily high of 5.7°C with nights around 0.5°C. Expect roughly 17 wet days totalling 59.7mm. A hard month to visit for comfort alone.
February in Hamm averages a daily high of 6.9°C with nights around 0.7°C. Expect roughly 13.9 wet days totalling 53.7mm. A hard month to visit for comfort alone.
March in Hamm averages a daily high of 10.5°C with nights around 2°C. Expect roughly 13 wet days totalling 49.5mm. Demanding conditions — pack for it and plan indoor options.
April in Hamm averages a daily high of 15.2°C with nights around 4.4°C. Expect roughly 10.4 wet days totalling 39.8mm. Generally workable, with some weather to plan around.
May in Hamm averages a daily high of 18.9°C with nights around 7.6°C. Expect roughly 13 wet days totalling 62.1mm. Generally workable, with some weather to plan around.
June in Hamm averages a daily high of 22.5°C with nights around 11.1°C. Expect roughly 12.4 wet days totalling 63.1mm. Comfortable conditions for being outdoors all day.
July in Hamm averages a daily high of 24.6°C with nights around 13°C. Expect roughly 14.2 wet days totalling 80.9mm. Generally workable, with some weather to plan around.
August in Hamm averages a daily high of 24.1°C with nights around 13.2°C. Expect roughly 14.3 wet days totalling 81mm. Generally workable, with some weather to plan around.
September in Hamm averages a daily high of 20.6°C with nights around 10.4°C. Expect roughly 11.4 wet days totalling 51.4mm. Comfortable conditions for being outdoors all day.
October in Hamm averages a daily high of 15.5°C with nights around 7.5°C. Expect roughly 12.1 wet days totalling 53.8mm. Generally workable, with some weather to plan around.
November in Hamm averages a daily high of 10.1°C with nights around 4.1°C. Expect roughly 14.3 wet days totalling 58.7mm. Demanding conditions — pack for it and plan indoor options.
December in Hamm averages a daily high of 6.7°C with nights around 1.7°C. Expect roughly 16.5 wet days totalling 58.7mm. 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. Hamm peaks at 77.
Based on 30 years of records, May–September scores highest for comfort in Hamm, balancing daytime temperature against rainfall.
July is the warmest, averaging a daily high of 24.6°C.
August is the wettest, averaging 81mm of rain across roughly 14.3 wet days.
January is the coolest month, with average daily highs around 5.7°C.