Hawaii County (Hilo)
September
Weather in Hawaii County, Hawaii for September 2025
Your guide to Hawaii County weather in September - trends and predictions
In general, the average temperature in Hawaii County at the beginning of September is 24.7 °F. As the month progressed, temperatures tended to slightly decrease, reaching an average of 24.4 °F by the end of September.
Hawaii County experiences heavy rainfall in September, with over 20 rainy days and an average total precipitation 141.7 mm.
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Temperatures
Rain 🌧️
More
0
Dry days
30
Rainy days
0
Snow days
25°/21°
Temperatures
15 km/h
Avg max wind
76 %
Avg humidity
Hawaii County Weather September
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Temperatures trend during September in Hawaii County
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September weather in Hawaii County day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Heavy rain at times | 25° /22° | 3.7 mm | 6 | |
| Sept. 2 |  Moderate rain at times | 25° /22° | 3.3 mm | 5 | |
| Sept. 3 |  Patchy rain possible | 25° /21° | 2.6 mm | 6 | |
| Sept. 4 |  Overcast | 25° /21° | 0.6 mm | 6 | |
| Sept. 5 |  Cloudy | 25° /21° | 0.8 mm | 6 | |
| Sept. 6 | Moderate rain at times | 24° /21° | 2.6 mm | 5 | |
| Sept. 7 | Patchy rain possible | 24° /21° | 3.8 mm | 5 | |
| Sept. 8 | Patchy rain possible | 25° /21° | 0.6 mm | 6 | |
| Sept. 9 | Overcast | 24° /21° | 0.3 mm | 5 | |
| Sept. 10 | Moderate rain at times | 26° /22° | 3.8 mm | 6 | |
| Sept. 11 | Moderate rain at times | 25° /21° | 8.6 mm | 6 | |
| Sept. 12 | Patchy rain possible | 26° /22° | 4.9 mm | 6 | |
| Sept. 13 | Patchy rain possible | 25° /22° | 5.5 mm | 6 | |
| Sept. 14 | Moderate rain at times | 24° /20° | 6.9 mm | 5 | |
| Sept. 15 | Moderate or heavy rain shower | 25° /21° | 14.9 mm | 6 | |
| Sept. 16 | Patchy rain possible | 25° /23° | 6.2 mm | 6 | |
| Sept. 17 | Moderate rain at times | 25° /22° | 7.7 mm | 6 | |
| Sept. 18 | Patchy rain possible | 25° /22° | 2.8 mm | 6 | |
| Sept. 19 | Heavy rain at times | 25° /21° | 8.6 mm | 5 | |
| Sept. 20 | Moderate or heavy rain shower | 23° /21° | 14.6 mm | 5 | |
| Sept. 21 | Heavy rain at times | 23° /20° | 7.1 mm | 5 | |
| Sept. 22 | Patchy rain possible | 24° /20° | 5.4 mm | 5 | |
| Sept. 23 | Moderate rain at times | 26° /20° | 4.4 mm | 6 | |
| Sept. 24 | Patchy rain possible | 25° /22° | 1 mm | 6 | |
| Sept. 25 | Patchy rain possible | 25° /21° | 4.6 mm | 5 | |
| Sept. 26 | Heavy rain at times | 24° /22° | 6.2 mm | 5 | |
| Sept. 27 | Moderate rain at times | 24° /22° | 6 mm | 5 | |
| Sept. 28 | Patchy rain possible | 23° /19° | 1.2 mm | 5 | |
| Sept. 29 | Patchy rain possible | 25° /20° | 1.4 mm | 6 | |
| Sept. 30 |  Partly cloudy | 25° /21° | 1.5 mm | 7 | |
| Next | |||||
Important Notice
Our weather forecast for Hawaii County in September is based on the analysis of historical data rather than real-time forecast models. While this provides a general overview, weather conditions can change. We recommend that you check the Hawaii County forecast closer to your planned date for the most up-to-date weather information.
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Hawaii County in September - FAQ
What are the expected maximum and minimum temperatures in Hawaii County during September?
During September, expect a variety of temperatures with highs around 25° and lows near 21°, suitable for diverse activities and preferences.
How much rainfall should be expected in Hawaii County during September?
Significant rainfall exceeding 141.7 mm is expected in Hawaii County during September, occurring over more than 30 days. Preparing for wet conditions is recommended in your planning.
What are the typical wind conditions in Hawaii County during September?
The average wind speed in Hawaii County during September is 15 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in Hawaii County
Explore the daily rainfall trends and prepare for Hawaii Countys September weather 💧
UV exposure in Hawaii County during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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Where is Hawaii County?Get accurate weather forecasts for Hawaii County, located at latitude 19.73 and longitude -155.091. Stay updated with localized weather information tailored for Hawaii County.
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