Click on a day for an hourly weather forecast
The temperatures in Waterbury in September are comfortable with low of 13°C and and high up to 24°C.
You can expect about 3 to 8 days of rain in Waterbury 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 Waterbury in September 2025.
If you’re planning to visit Waterbury in the near future, we highly recommend that you review the 14 day weather forecast for Waterbury before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 0° / -6° | 5 | 16 | 10 | 119 mm | Awful | Waterbury in January |
| February | 2° / -6° | 6 | 10 | 12 | 138 mm | Awful | Waterbury in February |
| March | 7° / -1° | 8 | 14 | 9 | 144 mm | Awful | Waterbury in March |
| April | 14° / 4° | 9 | 19 | 2 | 143 mm | Bad | Waterbury in April |
| May | 21° / 10° | 8 | 23 | 0 | 137 mm | Ok | Waterbury in May |
| June | 25° / 14° | 8 | 22 | 0 | 148 mm | Good | Waterbury in June |
| July | 29° / 18° | 10 | 21 | 0 | 167 mm | Ok | Waterbury in July |
| August | 28° / 17° | 7 | 24 | 0 | 160 mm | Good | Waterbury in August |
| September | 24° / 13° | 5 | 25 | 0 | 115 mm | Perfect | Waterbury in September |
| October | 17° / 8° | 7 | 24 | 1 | 155 mm | Ok | Waterbury in October |
| November | 10° / 2° | 6 | 22 | 2 | 112 mm | Bad | Waterbury in November |
| December | 4° / -2° | 7 | 16 | 8 | 161 mm | Awful | Waterbury in December |