Hilo Weather in September
With daytime temperatures of 26°C (79°F) and nighttime lows of 20°C (68°F), September in Hilo brings high temperatures during the day. Do keep in mind that quite a bit of rainfall is typical. Around 138 mm (5.4 in) falls on average.
Rainfall in Hilo in September
Typically, you can expect about 18 days of rain this month, with 138 mm (5.4 in) on average. Wet weather is a regular and significant part of this month. Frequent days of rain combined with high totals means proper waterproofs are worth packing.
Temperature in Hilo in September
September in Hilo brings typical temperatures with highs around 26°C (79°F) and lows of 20°C (68°F). The days can feel warmer than the evenings, so packing for both parts of the day is a good idea. With overnight lows of 20°C (68°F), evenings can feel noticeably cooler than the daytime. An extra layer is a good idea, though the cool air makes for a good night's sleep.
Sunshine in Hilo in September
The area experiences a moderate amount of sunshine, with approximately 160 hours of sunlight expected. This means a decent mix of sun and overcast.If you're a fan of comfortable temperatures and drier conditions, September is a great time to visit.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit the United States of America, check out our Hilo's climate page.
Hilo Temperature in September
Min Temperature
20°C (68°F)
Max Temperature
26°C (79°F)
Chance of Rain
59%
Precipitation
138 mm (5.4 in)
Rainy days
18 days
Humidity
78%
Sunshine
160 hours
Percentage Sunshine
45%
Daily Historical Temperatures
50-year average (1976-2025)
Based on our historical records, temperatures in Hilo typically stay consistent throughout September, with daily highs averaging around 26°C (79°F). Nights are warm, with lows around 21°C (70°F).
Average temperatures in September
Daily Historical Precipitation
50-year average (1976-2025)
Average daily rainfall for each day of the month based on long-term records.
Average precipitation in September
Historical weather for Hilo in September
Browse day-by-day weather records for Hilo spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.
Hilo historical weather extremes in September
Our historical data for Hilo spans 1998 to 2025, revealing these weather extremes.
- On September 27, 2019, temperatures climbed to 33°C (91°F), marking the warmest September day on record.
- The coldest September day was on September 5, 2021, with a maximum of 24°C (75°F).
- Hilo registered its coldest September night on September 15, 2009, with temperatures dropping to 18°C (64°F).
Best Places in the United States of America in September
Find out more about the weather in the United States of America and which places have the best travel conditions in this month. See all of the United States of America in September →
perfect weather
pleasant
tolerable
unpleasant
poor
What to Wear in Hilo in September
Warm but pleasant conditions in Hilo in September. Focus on lightweight, maybe with natural fabrics, cotton blend shirts, comfortable shorts, and breathable footwear. A light cover-up for sun protection is smart too. Expect heavy rainfall, so bring good rain protection and waterproof bags. It won't hurt to bring your sunglasses along, as you'll see some sunny periods.What To Do in Hilo in September
We rated the following activities from 1 (least suitable) to 10 (best) to do.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit the United States of America, check out our Hilo's climate page.
Temperature Rainfall Sunshine Humidity
See the full Hilo climate overview or explore weather in the United States of America.
