Click on a day for an hourly weather forecast
The temperatures in Mercer in September are comfortable with low of 17°C and and high up to 25°C.
You can expect about 3 to 8 days of rain in Mercer 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 Mercer in September 2025.
If you’re planning to visit Mercer in the near future, we highly recommend that you review the 14 day weather forecast for Mercer before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 3° / -3° | 6 | 18 | 7 | 89 mm | Awful | Mercer in January |
| February | 5° / -2° | 7 | 14 | 7 | 117 mm | Awful | Mercer in February |
| March | 9° / 2° | 7 | 18 | 5 | 127 mm | Awful | Mercer in March |
| April | 15° / 7° | 6 | 24 | 1 | 105 mm | Good | Mercer in April |
| May | 21° / 12° | 7 | 24 | 0 | 130 mm | Ok | Mercer in May |
| June | 26° / 17° | 7 | 23 | 0 | 131 mm | Good | Mercer in June |
| July | 29° / 21° | 9 | 22 | 0 | 180 mm | Ok | Mercer in July |
| August | 28° / 20° | 7 | 24 | 0 | 174 mm | Good | Mercer in August |
| September | 25° / 17° | 5 | 25 | 0 | 111 mm | Perfect | Mercer in September |
| October | 18° / 11° | 5 | 25 | 0 | 134 mm | Good | Mercer in October |
| November | 11° / 5° | 5 | 24 | 1 | 91 mm | Ok | Mercer in November |
| December | 7° / 1° | 7 | 20 | 5 | 142 mm | Awful | Mercer in December |