Click on a day for an hourly weather forecast
The temperatures in Hamilton in September are comfortable with low of 14°C and and high up to 22°C.
You can expect about 3 to 8 days of rain in Hamilton 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 Hamilton in September 2025.
If you’re planning to visit Hamilton in the near future, we highly recommend that you review the 14 day weather forecast for Hamilton before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | -3° / -7° | 8 | 6 | 18 | 97 mm | Awful | Hamilton in January |
| February | -2° / -7° | 8 | 4 | 17 | 96 mm | Awful | Hamilton in February |
| March | 4° / -2° | 10 | 12 | 10 | 109 mm | Awful | Hamilton in March |
| April | 10° / 3° | 9 | 16 | 4 | 139 mm | Awful | Hamilton in April |
| May | 17° / 9° | 8 | 23 | 0 | 131 mm | Ok | Hamilton in May |
| June | 22° / 14° | 7 | 23 | 0 | 140 mm | Ok | Hamilton in June |
| July | 25° / 17° | 9 | 22 | 0 | 156 mm | Good | Hamilton in July |
| August | 25° / 17° | 7 | 24 | 0 | 142 mm | Good | Hamilton in August |
| September | 22° / 14° | 5 | 25 | 0 | 97 mm | Good | Hamilton in September |
| October | 14° / 8° | 8 | 22 | 0 | 130 mm | Ok | Hamilton in October |
| November | 7° / 2° | 7 | 17 | 6 | 87 mm | Awful | Hamilton in November |
| December | 2° / -2° | 9 | 7 | 15 | 99 mm | Awful | Hamilton in December |