Click on a day for an hourly weather forecast
The weather in Castelldefels in September is hot. The average temperatures are between 20°C and 25°C.
You can expect rain for roughly half of the month of September in Castelldefels. We’re expecting roughly 8 to 15 days of rain, so your rubber boots and umbrella are going to see plenty of use this month if you’re keen on staying dry.
Our weather forecast can give you a great sense of what weather to expect in Castelldefels in September 2026.
If you’re planning to visit Castelldefels in the near future, we highly recommend that you review the 14 day weather forecast for Castelldefels before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 13° / 8° | 3 | 28 | 0 | 44 mm | Ok | Castelldefels in January |
| February | 14° / 8° | 4 | 25 | 0 | 37 mm | Good | Castelldefels in February |
| March | 15° / 10° | 5 | 26 | 0 | 56 mm | Good | Castelldefels in March |
| April | 17° / 12° | 6 | 24 | 0 | 62 mm | Good | Castelldefels in April |
| May | 21° / 15° | 6 | 25 | 0 | 47 mm | Good | Castelldefels in May |
| June | 25° / 19° | 5 | 25 | 0 | 34 mm | Perfect | Castelldefels in June |
| July | 28° / 22° | 4 | 28 | 0 | 28 mm | Perfect | Castelldefels in July |
| August | 28° / 23° | 5 | 26 | 0 | 42 mm | Perfect | Castelldefels in August |
| September | 25° / 20° | 8 | 22 | 0 | 82 mm | Good | Castelldefels in September |
| October | 22° / 17° | 6 | 25 | 0 | 99 mm | Good | Castelldefels in October |
| November | 17° / 12° | 5 | 25 | 0 | 69 mm | Good | Castelldefels in November |
| December | 14° / 9° | 3 | 28 | 0 | 28 mm | Good | Castelldefels in December |