Climate averages 1991–2020
Calais weather
in September.
A mild, moderately wet month: the 3rd warmest and the 8th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a mild month in Calais: daytime highs average 18.4°C and nights cool to about 13.2°C. By daytime temperature it is the 3rd warmest of the 12 months.
Expect about 68 mm of rain on roughly 11 days, which makes September a moderately wet month (the 8th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 42 min on an average September day.
The nearest other city in this atlas is Dunkirk (38 km away). In September its highs average 18.8°C, about as warm as Calais, with 57 mm of rain.
Among the 57 cities listed in France, Calais ranks 56th of 57 for the warmest September highs and joint 35th of 57 for the driest September (rainfall, lowest first). The mean September high of those 57 cities is 21.3°C; Calais is 2.9°C cooler than that mean.
From September to October, average highs fall by 3.5°C to 14.9°C, and monthly rainfall rises from 68 mm to 96 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
Calais climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 7.2°C3.4°C | 3.4°C | 79 | 14.3 | 8.58 h |
| February | 7.6°C3.3°C | 3.3°C | 60 | 11.5 | 10.010 h |
| March | 9.9°C4.7°C | 4.7°C | 51 | 10.5 | 11.812 h |
| April | 12.7°C6.6°C | 6.6°C | 45 | 9.3 | 13.814 h |
| May | 15.6°C9.6°C | 9.6°C | 51 | 9.8 | 15.516 h |
| June | 18.3°C12.4°C | 12.4°C | 49 | 8.7 | 16.416 h |
| July | 20.5°C14.8°C | 14.8°C | 51 | 9.6 | 16.016 h |
| August | 20.8°C15.2°C | 15.2°C | 65 | 10.0 | 14.615 h |
| September, selected | 18.4°C13.2°C | 13.2°C | 68 | 11.2 | 12.713 h |
| October | 14.9°C10.3°C | 10.3°C | 96 | 14.3 | 10.811 h |
| November | 10.7°C6.9°C | 6.9°C | 101 | 16.4 | 9.09 h |
| December | 7.8°C4.3°C | 4.3°C | 94 | 15.0 | 8.08 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
- Dunkirk in SeptemberFrance · 38 kmHigh 18.8°C · Low 12.6°C · 57 mm rain
- Saint Peters in SeptemberUnited Kingdom · 55 kmHigh 17.7°C · Low 13.3°C · 60 mm rain
- Hastings, United Kingdom in SeptemberUnited Kingdom · 90 kmHigh 18.1°C · Low 12.9°C · 66 mm rain
- Lille in SeptemberFrance · 91 kmHigh 19.3°C · Low 11.6°C · 53 mm rain
- Roubaix in SeptemberFrance · 97 kmHigh 19.2°C · Low 11.7°C · 54 mm rain
- Brugge in SeptemberBelgium · 100 kmHigh 18.5°C · Low 13.0°C · 62 mm rain
- Kortrijk in SeptemberBelgium · 100 kmHigh 19.0°C · Low 12.0°C · 54 mm rain
- Maidstone in SeptemberUnited Kingdom · 100 kmHigh 18.6°C · Low 11.9°C · 50 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 Calais) is explained once on the Calais year overview and on the Sources, method and limits page.