Hilo, Hawaii weather in September
Temperature, sea and sunshine in September: long-term averages from 30 years of weather data, not a forecast.
Holiday weather in September
Good
Best time to visit: January – December
What is the weather like in Hilo, Hawaii in September?
In September, Hilo, Hawaii is warm: daytime highs average 26 °C, and even at night it stays warm at around 22 °C. The sea averages 26.6 °C – lovely and warm for swimming. The sun shines for around 8 hours a day. It is the rainy season: rain falls on about 21 days, totalling 83 mm. The air is often humid and muggy. All in all, September is a good month for a holiday in Hilo, Hawaii.
September compared
How the weather changes from August to October. Tap a month to open it.
| AugustAug | SeptemberSep | OctoberOct | |
|---|---|---|---|
| Score | 68 | 66 | 65 |
| Day | 26° | 26° | 26° |
| Night | 22° | 22° | 21° |
| Sea | 26° | 27° | 27° |
| Sun | 8 h | 8 h | 7 h |
| Rain days | 23 | 21 | 20 |
More details for September
- Daylight
- 12 h 17 min06:07 – 18:24
- UV index
- 11 · extremeclear sky, noon (estimate)All months
- Muggy days
- 29 daysdew point 18 °C or moreAll months
- Wind
- 17 km/haverage daily peakAll months
- Cloud cover
- 54 %on averageAll months
- Hot days
- 0 days30 °C or moreAll months
- Time zone
- UTC−10Pacific/Honolulu
How the score comes together
- Temperatureweight 50 %100 %
- Sunshineweight 20 %82 %
- Few rainy daysweight 30 %0 %
Each factor is rated from 0 to 100 % and weighted for the travel style “Nature escape”.
What to pack in September
- Swimwear
- Sunscreen
- Sunglasses & sun hat
- Light, breathable clothes
- Insect repellent
- Rain jacket or umbrella
Hilo, Hawaii in September: quick answers
Is Hilo, Hawaii hot in September?
Warm rather than hot: in September, daytime highs in Hilo, Hawaii average 26 °C and nights cool to about 22 °C.
Can you swim in Hilo, Hawaii in September?
Yes. In September the sea averages 26.6 °C – lovely and warm for swimming.
Does it rain much in Hilo, Hawaii in September?
It rains often – on about 21 days, adding up to 83 mm.
Hilo, Hawaii month by month
The whole year in Hilo, HawaiiAll destinations: USAHawaii weather in SeptemberWhere to go in SeptemberSea temperature in September
Climate averages 1996–2025, not a forecast. Data: Copernicus ERA5 / ERA5-Land via Open-Meteo.com (CC BY 4.0), NOAA OISST, WMO 1991–2020 (NOAA NCEI), GeoNames (CC BY 4.0). Sources & licences