| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 9.2° | 3.2° | 67.3mm | 14.7 | 36 |
| February | 10.6° | 3.4° | 51.6mm | 12.9 | 44 |
| March | 13.3° | 4.4° | 51.4mm | 12.3 | 54 |
| April | 16.2° | 5.9° | 50.1mm | 11.6 | 65 |
| May | 19.5° | 9.2° | 57.3mm | 11.6 | 75 |
| June | 22.9° | 12.2° | 52.2mm | 10 | 80 |
| July | 24.9° | 13.7° | 46.8mm | 9.9 | 80 |
| August | 24.8° | 13.8° | 44.8mm | 9.4 | 81 |
| September | 22.2° | 11.5° | 49.1mm | 9.6 | 81 |
| October | 17.7° | 9.6° | 77.1mm | 14.9 | 63 |
| November | 12.7° | 5.9° | 73.9mm | 15.9 | 47 |
| December | 9.7° | 3.6° | 73.1mm | 15.3 | 37 |
January in Rennes averages a daily high of 9.2°C with nights around 3.2°C. Expect roughly 14.7 wet days totalling 67.3mm. Demanding conditions — pack for it and plan indoor options.
February in Rennes averages a daily high of 10.6°C with nights around 3.4°C. Expect roughly 12.9 wet days totalling 51.6mm. Demanding conditions — pack for it and plan indoor options.
March in Rennes averages a daily high of 13.3°C with nights around 4.4°C. Expect roughly 12.3 wet days totalling 51.4mm. Demanding conditions — pack for it and plan indoor options.
April in Rennes averages a daily high of 16.2°C with nights around 5.9°C. Expect roughly 11.6 wet days totalling 50.1mm. Generally workable, with some weather to plan around.
May in Rennes averages a daily high of 19.5°C with nights around 9.2°C. Expect roughly 11.6 wet days totalling 57.3mm. Comfortable conditions for being outdoors all day.
June in Rennes averages a daily high of 22.9°C with nights around 12.2°C. Expect roughly 10 wet days totalling 52.2mm. Comfortable conditions for being outdoors all day.
July in Rennes averages a daily high of 24.9°C with nights around 13.7°C. Expect roughly 9.9 wet days totalling 46.8mm. Comfortable conditions for being outdoors all day.
August in Rennes averages a daily high of 24.8°C with nights around 13.8°C. Expect roughly 9.4 wet days totalling 44.8mm. Comfortable conditions for being outdoors all day.
September in Rennes averages a daily high of 22.2°C with nights around 11.5°C. Expect roughly 9.6 wet days totalling 49.1mm. Comfortable conditions for being outdoors all day.
October in Rennes averages a daily high of 17.7°C with nights around 9.6°C. Expect roughly 14.9 wet days totalling 77.1mm. Generally workable, with some weather to plan around.
November in Rennes averages a daily high of 12.7°C with nights around 5.9°C. Expect roughly 15.9 wet days totalling 73.9mm. Demanding conditions — pack for it and plan indoor options.
December in Rennes averages a daily high of 9.7°C with nights around 3.6°C. Expect roughly 15.3 wet days totalling 73.1mm. Demanding conditions — pack for it and plan indoor options.
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. Rennes peaks at 81.
Based on 30 years of records, May–September scores highest for comfort in Rennes, balancing daytime temperature against rainfall.
July is the warmest, averaging a daily high of 24.9°C.
October is the wettest, averaging 77.1mm of rain across roughly 14.9 wet days.
January is the coolest month, with average daily highs around 9.2°C.