Weather in Rennes in September 2025
Average weather
Average temperature in Rennes in September
The expected average maximum temperature in September is +25°C with a maximum of +33°C and a minimum of +7°C.
The average maximum temperature goes up 0% by the end of the month, compared with the beginning of the month, from +22°C to +22°C.
Is Rennes warm or cold in September?
Rennes is typically mild in September.
Maximum temperatures go down compared to the previous month from +23°C to +21°C. The minimum temperature also goes down from +13°C to +11°C.
Pack a light jacket as it will be warm in the day and cool in the evenings.
September is one of the warmest months in Rennes, here is the comparison with other months:
Climate in Rennes in September
| August | September | October | ||||
|---|---|---|---|---|---|---|
| Avg. temperature | ||||||
| +23°C | +21°C | +16°C | ||||
| Min. temperature | ||||||
| +6°C | +3°C | -3°C | ||||
| Max. temperature | ||||||
| +38°C | +34°C | +28°C | ||||
| Rainfall | ||||||
| 42 mm | 45 mm | 67 mm | ||||
| Wind | ||||||
| 2 m/s | 2 m/s | 2 m/s | ||||
| Humidity | ||||||
| 74% | 77% | 83% | ||||
| Air pressure | ||||||
| 1016 HPa | 1016 HPa | 1014 HPa | ||||
| Sunny days | ||||||
| 7 | 7 | 4 | ||||
| Cloudy days | ||||||
| 8 | 8 | 9 | ||||
| Rainy days | ||||||
| 14 | 13 | 17 | ||||
| Snowy days | ||||||
| 0 | 0 | 0 | ||||
September typically has worse weather conditions compared to August. It’s getting colder in September. From +23°C in the day, the average maximum temperature lowers to +21°C. Prepare for more rain. Average rainfall goes from 42 mm to 45 mm. Humidity rises from 74% to 77%. The average wind speed doesn’t change much during September, staying around 2 m/s. The amount of sunny days stay about the same, averaging 7 sunny days during the month.
October brings much the same weather, it remains ok.
Wind
The average wind speed is 2 m/s getting up to 6 m/s which is a medium breeze. You can feel it, especially getting out of the water.
The average wind speed in Rennes is gradually decreasing during September, going from 3 m/s to 1 m/s over the course of the month.
Rain
How was the weather last September in Rennes?
Climate Change over Years
The climate in Rennes in September has not changed much over the last 43 years.
The average temperature was the lowest in 1986 (+14°C) and the highest in 2022 (+18°C). The driest year was 1996 with only 390 mm of rainfall, and the wettest year was 2000 with 878 mm.
FAQ
Is September a good time to visit Rennes?
Can you sunbathe in Rennes in September?
Is Rennes rainy in September?
Is it sunny in Rennes in September?
Other cities in France
Monthly weather in Rennes
Source of the data
For this page, we’ve looked at the typical weather in Rennes, based on historical hourly weather data from January 1, 1979, to December 31, 2023.
For past dates, we show actual recorded data at the location at that time. Forecasts are based on recorded weather during that day of the year, averaged over the total years for which we have records (unless stated otherwise). The daily temperature is the highest recorded temperature in the shadow during that day.