Click on a day for an hourly weather forecast
The temperatures in Nagano in August are comfortable with low of 18°C and and high up to 29°C.
There’s going to be many days of rain during the month of August in Nagano.
Nagano should expect an average of 15 to 22 days of rain, so be sure to bring along a waterproof jacket to stay dry this month!
Our weather forecast can give you a great sense of what weather to expect in Nagano in August 2025.
If you’re planning to visit Nagano in the near future, we highly recommend that you review the 14 day weather forecast for Nagano before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 2° / -6° | 21 | 1 | 19 | 85 mm | Awful | Nagano in January |
| February | 4° / -6° | 18 | 2 | 13 | 62 mm | Awful | Nagano in February |
| March | 9° / -2° | 14 | 10 | 8 | 60 mm | Awful | Nagano in March |
| April | 15° / 3° | 10 | 19 | 1 | 54 mm | Ok | Nagano in April |
| May | 21° / 9° | 9 | 23 | 0 | 51 mm | Ok | Nagano in May |
| June | 25° / 13° | 11 | 20 | 0 | 63 mm | Good | Nagano in June |
| July | 28° / 18° | 16 | 15 | 0 | 112 mm | Good | Nagano in July |
| August | 29° / 18° | 15 | 16 | 0 | 83 mm | Ok | Nagano in August |
| September | 25° / 14° | 12 | 18 | 0 | 83 mm | Good | Nagano in September |
| October | 19° / 8° | 11 | 21 | 0 | 73 mm | Ok | Nagano in October |
| November | 13° / 3° | 12 | 17 | 1 | 60 mm | Bad | Nagano in November |
| December | 5° / -2° | 18 | 4 | 13 | 85 mm | Awful | Nagano in December |