| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 5.3° | -0.3° | 49.8mm | 12.7 | 24 |
| February | 7.7° | 0.3° | 45.1mm | 11.2 | 36 |
| March | 12° | 2.6° | 51.7mm | 11.5 | 51 |
| April | 16.3° | 5.5° | 62.2mm | 11.3 | 66 |
| May | 20.1° | 9.6° | 97.6mm | 14.4 | 71 |
| June | 24.3° | 13.4° | 85.2mm | 12.5 | 75 |
| July | 25.9° | 15° | 89mm | 11.8 | 76 |
| August | 25.4° | 14.9° | 89.4mm | 12.3 | 75 |
| September | 21° | 11.2° | 68.1mm | 10.1 | 80 |
| October | 16.1° | 7.9° | 72.7mm | 12.5 | 63 |
| November | 9.3° | 3.3° | 65mm | 12.7 | 40 |
| December | 5.8° | 0.4° | 64.7mm | 14.4 | 23 |
January in Basel averages a daily high of 5.3°C with nights around -0.3°C. Expect roughly 12.7 wet days totalling 49.8mm. A hard month to visit for comfort alone.
February in Basel averages a daily high of 7.7°C with nights around 0.3°C. Expect roughly 11.2 wet days totalling 45.1mm. Demanding conditions — pack for it and plan indoor options.
March in Basel averages a daily high of 12°C with nights around 2.6°C. Expect roughly 11.5 wet days totalling 51.7mm. Demanding conditions — pack for it and plan indoor options.
April in Basel averages a daily high of 16.3°C with nights around 5.5°C. Expect roughly 11.3 wet days totalling 62.2mm. Generally workable, with some weather to plan around.
May in Basel averages a daily high of 20.1°C with nights around 9.6°C. Expect roughly 14.4 wet days totalling 97.6mm. Generally workable, with some weather to plan around.
June in Basel averages a daily high of 24.3°C with nights around 13.4°C. Expect roughly 12.5 wet days totalling 85.2mm. Comfortable conditions for being outdoors all day.
July in Basel averages a daily high of 25.9°C with nights around 15°C. Expect roughly 11.8 wet days totalling 89mm. Comfortable conditions for being outdoors all day.
August in Basel averages a daily high of 25.4°C with nights around 14.9°C. Expect roughly 12.3 wet days totalling 89.4mm. Comfortable conditions for being outdoors all day.
September in Basel averages a daily high of 21°C with nights around 11.2°C. Expect roughly 10.1 wet days totalling 68.1mm. Comfortable conditions for being outdoors all day.
October in Basel averages a daily high of 16.1°C with nights around 7.9°C. Expect roughly 12.5 wet days totalling 72.7mm. Generally workable, with some weather to plan around.
November in Basel averages a daily high of 9.3°C with nights around 3.3°C. Expect roughly 12.7 wet days totalling 65mm. Demanding conditions — pack for it and plan indoor options.
December in Basel averages a daily high of 5.8°C with nights around 0.4°C. Expect roughly 14.4 wet days totalling 64.7mm. 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. Basel peaks at 80.
Based on 30 years of records, June–September scores highest for comfort in Basel, balancing daytime temperature against rainfall.
July is the warmest, averaging a daily high of 25.9°C.
May is the wettest, averaging 97.6mm of rain across roughly 14.4 wet days.
January is the coolest month, with average daily highs around 5.3°C.