September weather forecastKeanakolu, HI
September
Weather in September
The first month of the autumn, September, is still a comfortable month in Keanakolu, Hawaii, with an average temperature fluctuating between 59°F (15°C) and 66.4°F (19.1°C).Temperature
A minimal variation is noted in Keanakolu's average high-temperature at the onset of September, reaching a still refreshing 66.4°F (19.1°C) from August's 67.5°F (19.7°C). September in Keanakolu is characterized by a steady nighttime low-temperature of 59°F (15°C).Humidity
September and October, with an average relative humidity of 84%, are the most humid months.Rainfall
In Keanakolu, during September, the rain falls for 27.3 days and regularly aggregates up to 3.31" (84mm) of precipitation. In Keanakolu, Hawaii, during the entire year, the rain falls for 280.8 days and collects up to 33.9" (861mm) of precipitation.Daylight
The average length of the day in September in Keanakolu is 12h and 14min.On the first day of the month, sunrise is at 6:05 am and sunset at 6:36 pm. On the last day of September, in Keanakolu, Hawaii, sunrise is at 6:12 am and sunset at 6:09 pm HST.
Sunshine
In Keanakolu, the average sunshine in September is 7.7h.UV index
May through October, with an average maximum UV index of 5, are months with the highest UV index in Keanakolu, Hawaii. A UV Index of 3 to 5 symbolizes a moderate threat to health from unprotected exposure to Sun's UV rays for ordinary individuals.Note: A maximum high UV index of 5 in September translates into the following recommendations:
Preventative actions are necessary - The mandate to avoid skin and eye damage is in place. UV radiation from the Sun is most dangerous during midday; take precautions and seek shade. Sun-related eye harm can be minimized with proper sunglasses offering UVA and UVB coverage.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Keanakolu, HI
- Average high temperature in September: 66.4°F
The warmest month (with the highest average high temperature) is August (67.5°F).
The month with the lowest average high temperature is March (61.9°F).
- Average low temperature in September: 59°F
The month with the highest average low temperature is September (59°F).
The coldest month (with the lowest average low temperature) is February (52°F).
Average pressure in September
Keanakolu, 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
Keanakolu, HI
- Average wind speed in September: 4.6mph
The windiest months (with the highest average wind speed) are July and August (5.5mph).
The calmest months (with the lowest average wind speed) are January, May and October (4.5mph).
Average humidity in September
Keanakolu, HI
- Average humidity in September: 84%
The months with the highest relative humidity are September and October (84%).
The month with the lowest relative humidity is February (78%).
Average rainfall in September
Keanakolu, HI
- Average rainfall in September: 3.31"
The wettest month (with the highest rainfall) is August (4.13").
The driest month (with the least rainfall) is June (1.57").
Average rainfall days in September
Keanakolu, HI
- Average rainfall days in September: 27.3 days
The month with the highest number of rainy days is September (27.3 days).
The month with the least rainy days is January (17.1 days).
Average daylight in September /
Average sunshine in September
Keanakolu, 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: 7h and 42min
The month with the most sunshine is July (Average sunshine: 10h and 0min).
The month with the least sunshine is December (Average sunshine: 6h and 30min).
Average sunshine days in September
Keanakolu, HI
- Average sunshine days in September: 0.8 days
The month with the most sunshine days is January (9.7 days).
The month with the least sunshine days is September (0.8 days).
Average UV index in September
Keanakolu, HI
- Average UV index in September: 5
The months with the highest UV index are May, June, July, August, September and October (UV index 5).
The months with the lowest UV index are January, February, March, April, November and December (UV index 4).
Average cloud cover in September
Keanakolu, HI
- Average cloud cover in September: 43
The months with the most cloud cover are April and September (Cloud cover 43).
The month with the least cloud cover is January (Cloud cover 29).
Average visibility in September
Keanakolu, 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).
