Calais weather in September
Temperature, sea and sunshine in September: long-term averages from 30 years of weather data, not a forecast.
Holiday weather in September
Poor
Best time to visit: July – August
What is the weather like in Calais in September?
In September, Calais is mild: daytime highs average 19 °C, and nights cool down to about 13 °C. The sea averages 17.6 °C – bracing, so a wetsuit helps for longer swims. Expect around 6 hours of sunshine a day. Rain is frequent, with about 11 rainy days and 65 mm in total. All in all, September is not an ideal month for a holiday in Calais.
September compared
How the weather changes from August to October. Tap a month to open it.
| AugustAug | SeptemberSep | OctoberOct | |
|---|---|---|---|
| Score | 39 | 21 | 9 |
| Day | 21° | 19° | 15° |
| Night | 15° | 13° | 10° |
| Sea | 18° | 18° | 16° |
| Sun | 7 h | 6 h | 4 h |
| Rain days | 11 | 11 | 14 |
More details for September
- Daylight
- 12 h 44 min07:26 – 20:10
- UV index
- 4 · moderateclear sky, noon (estimate)All months
- Muggy days
- 0 daysdew point 18 °C or moreAll months
- Wind
- 22 km/haverage daily peakAll months
- Cloud cover
- 62 %on averageAll months
- Hot days
- 0 days30 °C or more
- Snow days
- 0 days1 cm or more of fresh snow
- Time zone
- UTC+2Europe/Paris
How the score comes together
- Temperatureweight 35 %0 %
- Seaweight 25 %9 %
- Sunshineweight 20 %42 %
- Few rainy daysweight 20 %54 %
Each factor is rated from 0 to 100 % and weighted for the travel style “Sun, sea & sand”.
What to pack in September
- Wetsuit for longer swims
- Sunscreen
- A jumper for the evenings
- Rain jacket or umbrella
Calais in September: quick answers
Is Calais hot in September?
No. In September, Calais is mild: daytime highs average 19 °C and nights drop to about 13 °C.
Can you swim in Calais in September?
Only if you don't mind cold water: in September the sea averages just 17.6 °C. Comfortable swimming temperatures are not reached at any time of year.
Does it rain much in Calais in September?
Rain is frequent, with about 11 rainy days and 65 mm in total.
Calais month by month
The whole year in CalaisAll destinations: FranceWhere to go in SeptemberSea temperature in September
Climate averages 1996–2025, not a forecast. Data: Copernicus ERA5 / ERA5-Land via Open-Meteo.com (CC BY 4.0), NOAA OISST, WMO 1991–2020 (NOAA NCEI), GeoNames (CC BY 4.0). Sources & licences