September weather forecastKapaau, HI
September
Weather in September
The first month of the autumn, September, is also an enjoyable month in Kapaau, Hawaii, with an average temperature fluctuating between 66.4°F (19.1°C) and 59°F (15°C).Temperature
With the start of September, Kapaau measures an average high-temperature of a still comfortable 66.4°F (19.1°C), not significantly differing from August's 67.5°F (19.7°C). During September, Kapaau's nighttime temperatures demonstrate a subtle cooling from daytime highs, stabilizing at a moderate 59°F (15°C).Humidity
The months with the highest humidity are September and October, with an average relative humidity of 84%.Rainfall
In Kapaau, in September, during 27.3 rainfall days, 3.31" (84mm) of precipitation is typically accumulated. In Kapaau, 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 is 12h and 15min.On the first day of September, sunrise is at 6:07 am and sunset at 6:38 pm. On the last day of the month, sunrise is at 6:14 am and sunset at 6:11 pm HST.
Sunshine
In Kapaau, 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. A UV Index value of 3 to 5 symbolizes a moderate threat to health from unsafe exposure to UV radiation for the average person.Note: In September, an average UV index of 5 transforms into the following instructions:
Be careful. Light complexion individuals might get burns in fewer than 30 minutes. It's recommended to limit sun exposure when its radiation is at its peak during midday. Tightly woven clothing, when worn loosely, shields effectively against the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Kapaau, 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
Kapaau, 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
Kapaau, 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
Kapaau, 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
Kapaau, 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
Kapaau, 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
Kapaau, 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: 10h and 54min).
- 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
Kapaau, 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
Kapaau, 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
Kapaau, 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
Kapaau, 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).
