Click on a day for an hourly weather forecast
The weather in Williamstown in August is hot. The average temperatures are between 21°C and 29°C.
You can expect rain for roughly half of the month of August in Williamstown. We’re expecting roughly 8 to 15 days of rain, so your rubber boots and umbrella are going to see plenty of use this month if you’re keen on staying dry.
Our weather forecast can give you a great sense of what weather to expect in Williamstown in August 2025.
If you’re planning to visit Williamstown in the near future, we highly recommend that you review the 14 day weather forecast for Williamstown before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 4° / -2° | 8 | 20 | 3 | 84 mm | Awful | Williamstown in January |
| February | 6° / -2° | 8 | 17 | 3 | 97 mm | Awful | Williamstown in February |
| March | 11° / 2° | 8 | 21 | 2 | 115 mm | Awful | Williamstown in March |
| April | 17° / 8° | 7 | 23 | 0 | 102 mm | Ok | Williamstown in April |
| May | 22° / 13° | 8 | 23 | 0 | 100 mm | Ok | Williamstown in May |
| June | 27° / 18° | 10 | 20 | 0 | 121 mm | Good | Williamstown in June |
| July | 30° / 21° | 11 | 20 | 0 | 124 mm | Ok | Williamstown in July |
| August | 29° / 21° | 10 | 21 | 0 | 135 mm | Ok | Williamstown in August |
| September | 25° / 17° | 7 | 23 | 0 | 106 mm | Good | Williamstown in September |
| October | 19° / 11° | 7 | 24 | 0 | 135 mm | Ok | Williamstown in October |
| November | 12° / 5° | 5 | 25 | 0 | 82 mm | Ok | Williamstown in November |
| December | 8° / 1° | 7 | 23 | 1 | 126 mm | Bad | Williamstown in December |