September weather forecastHilo, HI
September
Weather in September
With the warmest sea temperature in the year at 79.3°F (26.3°C), September calls on all sea lovers for a splash in its azure waters. This month witnesses a slight reduction in daylight hours, yet retains a significant amount of sunshine and maintains a pleasant overall climate. Hilo’s vivid city life coupled with its picturesque landscapes creates an unforgettable allure during this period. Local cultural fairs and food festivals during September add a special flavor to the city's experience. The shift towards fewer daylight hours gives the dusk and dawn hues a certain depth, enriching the city's charming panoramas.Temperature
Hilo's shift into September sets the average high-temperature at a still warm 75.2°F (24°C), a figure that deviates only slightly from August's 75.4°F (24.1°C). Hilo, during September nights, records a temperature marginally cooler than the daytime average, at a pleasant 70°F (21.1°C).Humidity
In September, the average relative humidity in Hilo, Hawaii, is 79%.Rainfall
In Hilo, in September, during 19.2 rainfall days, 1.81" (46mm) of precipitation is typically accumulated. In Hilo, during the entire year, the rain falls for 227.7 days and collects up to 27.83" (707mm) of precipitation.Ocean temperature
September is the month with the warmest seawater, with an average ocean temperature of 79.3°F (26.3°C).Note: Surface water temperatures falling between 77°F (25°C) and 84.2°F (29°C) are regarded as prime and extremely agreeable for enduring periods during any water activity.
Daylight
The average length of the day in September in Hilo is 12h and 14min.On the first day of September in Hilo, sunrise is at 6:05 am and sunset at 6:35 pm. On the last day of the month, sunrise is at 6:11 am and sunset at 6:08 pm HST.
Sunshine
In Hilo, the average sunshine in September is 8.8h.UV index
The months with the highest UV index in Hilo, Hawaii, are May through December, with an average maximum UV index of 6. A UV Index estimate of 6 to 7 represents a high health risk from unsafe exposure to UV radiation for average individuals.Note: An average UV index of 6 in September transforms into this advice:
Implement preventive steps and embrace sun safety standards. Protection from skin and eye distress is compulsory. Remember that the sun's UV radiation is strongest between 10 a.m. and 4 p.m. Make an effort to avoid direct sun exposure during these hours. Opt for tightly woven and loose clothing to enhance protection from the Sun. Heads up! Sand and water reflection magnifies the UV exposure from the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Hilo, HI
- Average high temperature in September: 75.2°F
The warmest month (with the highest average high temperature) is August (75.4°F).
The month with the lowest average high temperature is March (69.6°F).
- Average low temperature in September: 70°F
The month with the highest average low temperature is September (70°F).
The coldest month (with the lowest average low temperature) is March (64°F).
Average pressure in September
Hilo, HI
- Average pressure in September: 29.97"Hg
The month with the highest atmospheric pressure is April (30.05"Hg).
The months with the lowest atmospheric pressure are September and October (29.97"Hg).
Average wind speed in September
Hilo, HI
- Average wind speed in September: 7mph
The windiest month (with the highest average wind speed) is August (7.6mph).
The calmest month (with the lowest average wind speed) is October (6.7mph).
Average humidity in September
Hilo, HI
- Average humidity in September: 79%
The month with the highest relative humidity is March (80%).
The months with the lowest relative humidity are January, May, June and July (78%).
Average rainfall in September
Hilo, HI
- Average rainfall in September: 1.81"
The wettest month (with the highest rainfall) is February (3.78").
The driest month (with the least rainfall) is June (1.1").
Average rainfall days in September
Hilo, HI
- Average rainfall days in September: 19.2 days
The month with the highest number of rainy days is March (22.9 days).
The month with the least rainy days is January (13.3 days).
Average sea temperature in September
Hilo, HI
- Average sea temperature in September: 79.3°F
The best month for swimming (with the highest average sea temperature) is September (79.3°F).
The coldest month (with the lowest average sea temperature) is March (75.7°F).
Average daylight in September /
Average sunshine in September
Hilo, HI
- Average daylight in September: 12h and 12min
The month with the longest days is June (Average daylight: 13h and 18min).
The month with the shortest days is December (Average daylight: 11h and 0min).
- Average sunshine in September: 8h and 48min
The month with the most sunshine is June (Average sunshine: 10h and 54min).
The month with the least sunshine is December (Average sunshine: 6h and 30min).
Average sunshine days in September
Hilo, HI
- Average sunshine days in September: 2.5 days
The month with the most sunshine days is January (12.1 days).
The month with the least sunshine days is August (1.8 days).
Average UV index in September
Hilo, HI
- Average UV index in September: 6
The months with the highest UV index are May, June, July, August, September, October, November and December (UV index 6).
The months with the lowest UV index are January, February, March and April (UV index 5).
Average cloud cover in September
Hilo, HI
- Average cloud cover in September: 29
The month with the most cloud cover is March (Cloud cover 42).
The month with the least cloud cover is January (Cloud cover 26).
Average visibility in September
Hilo, HI
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
