Climate averages 1991–2020
Aulnay-sous-Bois weather
in September.
A mild, moderately wet month: the 4th warmest and the driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a mild month in Aulnay-sous-Bois: daytime highs average 20.6°C and nights cool to about 12.0°C. By daytime temperature it is the 4th warmest of the 12 months.
Expect about 45 mm of rain on roughly 8 days, which makes September a moderately wet month (the driest month of the year). Daylight, from sunrise to sunset, lasts about 12 h 39 min on an average September day.
The nearest other city in this atlas is Paris 20 Ménilmontant (11 km away). In September its highs average 20.3°C, about as warm as Aulnay-sous-Bois, with 48 mm of rain.
Among the 57 cities listed in France, Aulnay-sous-Bois ranks joint 30th of 57 for the warmest September highs and 3rd of 57 for the driest September (rainfall, lowest first). The mean September high of those 57 cities is 21.3°C; Aulnay-sous-Bois is 0.6°C cooler than that mean.
From September to October, average highs fall by 4.6°C to 16.0°C, and monthly rainfall rises from 45 mm to 63 mm.
The annual picture
September in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Aulnay-sous-Bois climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 7.0°C1.9°C | 1.9°C | 56 | 11.7 | 8.79 h |
| February | 8.2°C1.6°C | 1.6°C | 50 | 10.2 | 10.110 h |
| March | 11.7°C3.5°C | 3.5°C | 51 | 10.5 | 11.912 h |
| April | 15.1°C5.9°C | 5.9°C | 51 | 10.4 | 13.714 h |
| May | 18.5°C9.6°C | 9.6°C | 63 | 10.9 | 15.315 h |
| June | 21.8°C12.8°C | 12.8°C | 54 | 10.0 | 16.116 h |
| July | 24.1°C15.0°C | 15.0°C | 52 | 9.1 | 15.716 h |
| August | 24.3°C14.9°C | 14.9°C | 58 | 9.2 | 14.414 h |
| September, selected | 20.6°C12.0°C | 12.0°C | 45 | 8.4 | 12.713 h |
| October | 16.0°C9.1°C | 9.1°C | 63 | 10.8 | 10.811 h |
| November | 10.7°C5.2°C | 5.2°C | 60 | 11.4 | 9.29 h |
| December | 7.4°C2.5°C | 2.5°C | 72 | 12.5 | 8.38 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
September in nearby cities
- Paris 20 Ménilmontant in SeptemberFrance · 11 kmHigh 20.3°C · Low 11.6°C · 48 mm rain
- Paris in SeptemberFrance · 14 kmHigh 20.6°C · Low 11.9°C · 47 mm rain
- Paris 13 Gobelins in SeptemberFrance · 16 kmHigh 20.6°C · Low 11.9°C · 47 mm rain
- Marne La Vallée in SeptemberFrance · 16 kmHigh 20.3°C · Low 11.9°C · 51 mm rain
- Créteil in SeptemberFrance · 16 kmHigh 20.7°C · Low 12.1°C · 48 mm rain
- Paris 15 Vaugirard in SeptemberFrance · 18 kmHigh 20.7°C · Low 12.1°C · 47 mm rain
- Argenteuil in SeptemberFrance · 18 kmHigh 20.6°C · Low 12.1°C · 44 mm rain
- Boulogne-Billancourt in SeptemberFrance · 22 kmHigh 20.7°C · Low 12.3°C · 47 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Aulnay-sous-Bois) is explained once on the Aulnay-sous-Bois year overview and on the Sources, method and limits page.