Click on a day for an hourly weather forecast
The temperatures in Fairfax in September are comfortable with low of 17°C and and high up to 27°C.
You can expect about 3 to 8 days of rain in Fairfax 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 Fairfax in September 2025.
If you’re planning to visit Fairfax in the near future, we highly recommend that you review the 14 day weather forecast for Fairfax before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 5° / -2° | 6 | 18 | 7 | 105 mm | Awful | Fairfax in January |
| February | 7° / -1° | 8 | 15 | 6 | 124 mm | Awful | Fairfax in February |
| March | 12° / 3° | 8 | 19 | 4 | 127 mm | Awful | Fairfax in March |
| April | 18° / 8° | 8 | 22 | 0 | 128 mm | Ok | Fairfax in April |
| May | 24° / 14° | 9 | 22 | 0 | 162 mm | Good | Fairfax in May |
| June | 29° / 18° | 7 | 23 | 0 | 142 mm | Ok | Fairfax in June |
| July | 32° / 21° | 7 | 24 | 0 | 158 mm | Ok | Fairfax in July |
| August | 31° / 20° | 7 | 24 | 0 | 162 mm | Ok | Fairfax in August |
| September | 27° / 17° | 5 | 25 | 0 | 130 mm | Perfect | Fairfax in September |
| October | 20° / 11° | 5 | 26 | 0 | 143 mm | Good | Fairfax in October |
| November | 13° / 5° | 5 | 25 | 1 | 100 mm | Ok | Fairfax in November |
| December | 8° / 1° | 7 | 21 | 3 | 134 mm | Awful | Fairfax in December |