Click on a day for an hourly weather forecast
The temperatures in Janesville in August are comfortable with low of 17°C and and high up to 26°C.
You can expect rain for roughly half of the month of August in Janesville. 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 Janesville in August 2025.
If you’re planning to visit Janesville in the near future, we highly recommend that you review the 14 day weather forecast for Janesville before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | -3° / -11° | 8 | 18 | 5 | 48 mm | Awful | Janesville in January |
| February | -1° / -10° | 7 | 16 | 5 | 46 mm | Awful | Janesville in February |
| March | 7° / -2° | 7 | 20 | 4 | 72 mm | Awful | Janesville in March |
| April | 13° / 3° | 8 | 21 | 1 | 114 mm | Bad | Janesville in April |
| May | 20° / 10° | 9 | 22 | 0 | 115 mm | Ok | Janesville in May |
| June | 25° / 15° | 9 | 21 | 0 | 138 mm | Good | Janesville in June |
| July | 27° / 18° | 7 | 24 | 0 | 96 mm | Good | Janesville in July |
| August | 26° / 17° | 8 | 24 | 0 | 92 mm | Good | Janesville in August |
| September | 23° / 13° | 6 | 24 | 0 | 90 mm | Perfect | Janesville in September |
| October | 15° / 6° | 8 | 23 | 0 | 91 mm | Ok | Janesville in October |
| November | 7° / 0° | 6 | 23 | 1 | 58 mm | Ok | Janesville in November |
| December | 1° / -6° | 8 | 20 | 3 | 61 mm | Awful | Janesville in December |