Click on a day for an hourly weather forecast
The temperatures in Darien in September are comfortable with low of 15°C and and high up to 24°C.
You can expect about 3 to 8 days of rain in Darien during the month of September. It’s a good idea to bring along your umbrella so that you don’t get caught in poor weather.
Our weather forecast can give you a great sense of what weather to expect in Darien in September 2025.
If you’re planning to visit Darien in the near future, we highly recommend that you review the 14 day weather forecast for Darien before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | -1° / -8° | 8 | 18 | 5 | 54 mm | Awful | Darien in January |
| February | 0° / -7° | 8 | 16 | 4 | 62 mm | Awful | Darien in February |
| March | 8° / 0° | 8 | 21 | 3 | 79 mm | Awful | Darien in March |
| April | 14° / 5° | 9 | 21 | 1 | 124 mm | Ok | Darien in April |
| May | 20° / 11° | 10 | 21 | 0 | 134 mm | Ok | Darien in May |
| June | 26° / 17° | 10 | 20 | 0 | 142 mm | Good | Darien in June |
| July | 28° / 19° | 9 | 22 | 0 | 100 mm | Good | Darien in July |
| August | 27° / 19° | 9 | 22 | 0 | 102 mm | Good | Darien in August |
| September | 24° / 15° | 7 | 23 | 0 | 78 mm | Good | Darien in September |
| October | 16° / 9° | 8 | 23 | 0 | 103 mm | Ok | Darien in October |
| November | 9° / 2° | 6 | 24 | 1 | 55 mm | Ok | Darien in November |
| December | 2° / -4° | 7 | 22 | 3 | 62 mm | Awful | Darien in December |