Click on a day for an hourly weather forecast
The weather in Hilo in September is hot. The average temperatures are between 21°C and 25°C.
You can expect about 3 to 8 days of rain in Hilo 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 Hilo in September 2025.
If you’re planning to visit Hilo in the near future, we highly recommend that you review the 14 day weather forecast for Hilo before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 23° / 19° | 3 | 28 | 0 | 107 mm | Perfect | Hilo in January |
| February | 22° / 18° | 5 | 23 | 0 | 163 mm | Good | Hilo in February |
| March | 21° / 18° | 7 | 24 | 0 | 190 mm | Ok | Hilo in March |
| April | 21° / 18° | 4 | 26 | 0 | 119 mm | Good | Hilo in April |
| May | 22° / 18° | 3 | 28 | 0 | 99 mm | Good | Hilo in May |
| June | 23° / 19° | 2 | 28 | 0 | 61 mm | Perfect | Hilo in June |
| July | 24° / 20° | 2 | 29 | 0 | 89 mm | Perfect | Hilo in July |
| August | 24° / 20° | 4 | 27 | 0 | 146 mm | Perfect | Hilo in August |
| September | 25° / 21° | 3 | 27 | 0 | 100 mm | Perfect | Hilo in September |
| October | 25° / 22° | 4 | 27 | 0 | 138 mm | Perfect | Hilo in October |
| November | 23° / 20° | 4 | 26 | 0 | 153 mm | Perfect | Hilo in November |
| December | 22° / 19° | 4 | 27 | 0 | 151 mm | Good | Hilo in December |