September weather forecastMaunaloa, HI
September
Weather in September
As autumn arrives in September, Maunaloa witnesses another peak in temperature, matching August’s high of 80.2°F (26.8°C). Despite the decrease in daylight hours, September remains bathed in sunlight for a good part of the day. Trade wind activity resumes, bringing back cooler breezes from the sea. With the temperature of the sea maintaining its warmth, water activities continue to thrive. During September, a slight increase in rainfall is recorded, hinting at the arrival of the wetter season.Temperature
In Maunaloa, the months of August and September are known for the peak temperatures, reaching an average high of 80.2°F (26.8°C).Humidity
In Maunaloa, the average relative humidity in September is 75%.Rainfall
In Maunaloa, during September, the rain falls for 10.1 days and regularly aggregates up to 0.75" (19mm) of precipitation. Throughout the year, there are 126.4 rainfall days, and 9.84" (250mm) of precipitation is accumulated.Ocean temperature
The months with the warmest seawater in Maunaloa are September and October, with an average ocean temperature of 80.6°F (27°C).Note: In water temperatures ranging between 77°F (25°C) and 84.2°F (29°C), activities such as swimming and diving become highly pleasurable for long durations.
Daylight
The average length of the day in September in Maunaloa is 12h and 15min.On the first day of the month, sunrise is at 6:12 am and sunset at 6:44 pm. On the last day of September, sunrise is at 6:19 am and sunset at 6:17 pm HST.
Sunshine
In Maunaloa, the average sunshine in September is 9.5h.UV index
The months with the highest UV index in Maunaloa are June through October, with an average maximum UV index of 7. A UV Index value of 6 to 7 symbolizes a high health hazard from unprotected exposure to Sun's UV rays for the ordinary person.Note: The daily high UV index of 7 in September translates into this advice:
Guard against overexposure. Protection from sun-induced harm is essential. The Sun's UV radiation is most intense from 10 a.m. to 4 p.m. Try to avoid direct sun exposure during these hours. Combat UV radiation's detrimental effects with sun-safe clothing and UV-blocking eyewear. Be attentive! The UV exposure is heightened with reflections from sand and water.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Maunaloa, HI
- Average high temperature in September: 80.2°F
The warmest months (with the highest average high temperature) are August and September (80.2°F).
The month with the lowest average high temperature is February (74.3°F).
- Average low temperature in September: 77.2°F
The months with the highest average low temperature are September and October (77.2°F).
The coldest month (with the lowest average low temperature) is March (71.2°F).
Average pressure in September
Maunaloa, HI
- Average pressure in September: 29.97"Hg
The months with the highest atmospheric pressure are March and April (30.05"Hg).
The months with the lowest atmospheric pressure are September and October (29.97"Hg).
Average wind speed in September
Maunaloa, HI
- Average wind speed in September: 11.8mph
The windiest month (with the highest average wind speed) is July (13.9mph).
The calmest month (with the lowest average wind speed) is January (10.8mph).
Average humidity in September
Maunaloa, HI
- Average humidity in September: 75%
The months with the highest relative humidity are April, May, June, July and August (76%).
The months with the lowest relative humidity are January and November (74%).
Average rainfall in September
Maunaloa, HI
- Average rainfall in September: 0.75"
The wettest month (with the highest rainfall) is March (1.3").
The driest month (with the least rainfall) is July (0.31").
Average rainfall days in September
Maunaloa, HI
- Average rainfall days in September: 10.1 days
The month with the highest number of rainy days is March (13.2 days).
The month with the least rainy days is July (8.5 days).
Average sea temperature in September
Maunaloa, HI
- Average sea temperature in September: 81°F
The best months for swimming (with the highest average sea temperature) are September and October (81°F).
The coldest months (with the lowest average sea temperature) are January, February, March and April (75°F).
Average daylight in September /
Average sunshine in September
Maunaloa, HI
- Average daylight in September: 12h and 18min
The month with the longest days is June (Average daylight: 13h and 24min).
The month with the shortest days is December (Average daylight: 10h and 54min).
- Average sunshine in September: 9h and 30min
The month with the most sunshine is June (Average sunshine: 11h and 30min).
The month with the least sunshine is December (Average sunshine: 6h and 48min).
Average sunshine days in September
Maunaloa, HI
- Average sunshine days in September: 12.7 days
The month with the most sunshine days is July (16.1 days).
The month with the least sunshine days is November (10.8 days).
Average UV index in September
Maunaloa, HI
- Average UV index in September: 7
The months with the highest UV index are June, July, August, September and October (UV index 7).
The months with the lowest UV index are January, February, March, April, May, November and December (UV index 6).
Average cloud cover in September
Maunaloa, HI
- Average cloud cover in September: 23
The months with the most cloud cover are February and March (Cloud cover 30).
The month with the least cloud cover is September (Cloud cover 23).
Average visibility in September
Maunaloa, 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).
