September weather forecast
Kalaoa, HI

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Weather in September

September marks the descent from the highs of summer. While it keeps up with August's heat, it brings in slightly more rain, hinting at the transition to autumn. Though October sees a further dip in temperature, it follows September's lead in terms of rainfall. The weather at this time of the year still resembles the summer months but with signs of the upcoming cooler autumn. It's a blend of seasonal changes that allows a unique mix of warm days and slightly cooler nights.

Temperature

The onset of September manifests an average high-temperature of a still moderately hot 78.3°F (25.7°C), demonstrating a minor variation from the preceding month. September nights cool to an average low-temperature of 74.8°F (23.8°C), a marginal decrease from its daytime equivalent.

Humidity

The average relative humidity in September is 76%.

Rainfall

In Kalaoa, Hawaii, in September, it is raining for 13.4 days, with typically 0.75" (19mm) of accumulated precipitation. In Kalaoa, during the entire year, the rain falls for 136 days and collects up to 8.5" (216mm) of precipitation.

Daylight

In September, the average length of the day is 12h and 14min.
On the first day of September, sunrise is at 6:08 am and sunset at 6:38 pm. On the last day of the month, sunrise is at 6:14 am and sunset at 6:12 pm HST.

Sunshine

In Kalaoa, Hawaii, the average sunshine in September is 9.5h.

UV index

January through December, with an average maximum UV index of 6, are months with the highest UV index in Kalaoa. The months with the lowest UV index are January through December, with an average maximum UV index of 6. A UV Index estimate of 6 to 7 represents a high health risk from exposure to the Sun's UV radiation for ordinary individuals.
Note: The UV index of 6 during September translates into the following guidance:
Conform to measures and uphold sun safety traditions. Warding off skin and eye harm is necessary. Avoid direct sunlight between the hours of 10 a.m. and 4 p.m., when UV radiation is at its peak. Keep in mind that shade structures may not provide complete protection. A wide-brimmed hat is a staple for defending the face, eyes, ears, and neck from the Sun.
Updated: Jul 27, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are September temperatures?

In Kalaoa, 78.3°F (25.7°C) is the average high-temperature and 74.8°F (23.8°C) is the average low-temperature during September.

What is the average humidity in September?

The average relative humidity in September is 76%.

How many days does it rain in September?

In Kalaoa, in September, it is raining for 13.4 days, with typically 0.75" (19mm) of accumulated precipitation.

How many hours of daylight does Kalaoa have in September?

The average day length in September is 12h and 14min.

When is the sunrise / sunset in September?

On the first day of September, sunrise is at 6:08 am and sunset at 6:38 pm. On the last day of the month, sunrise is at 6:14 am and sunset at 6:12 pm HST.

How long on average sun shines in September?

In Kalaoa, the average sunshine duration in September is 9.5h.

When is the highest UV index?

January through December, with an average maximum UV index of 6, are months with the highest UV index in Kalaoa.

What are the months with the lowest UV index?

January through December, with an average maximum UV index of 6, are months with the lowest UV index.

What is the UV index intensity in September?

The average daily maximum UV index in September is 6. A UV Index reading of 6 to 7 represents a high health threat from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Kalaoa, HI

Average temperature in September - Kalaoa, HI
  • Average high temperature in September: 78.3°F

The warmest month (with the highest average high temperature) is August (78.4°F).
The month with the lowest average high temperature is February (73.2°F).

  • Average low temperature in September: 74.8°F

The months with the highest average low temperature are August, September and October (74.8°F).
The coldest month (with the lowest average low temperature) is March (69.4°F).

Average pressure in September
Kalaoa, HI

Average pressure in September - Kalaoa, HI
  • Average pressure in September: 29.96"Hg

The month with the highest atmospheric pressure is April (30.04"Hg).
The months with the lowest atmospheric pressure are September and October (29.96"Hg).

Average wind speed in September
Kalaoa, HI

Average wind speed in September - Kalaoa, HI
  • Average wind speed in September: 5.2mph

The windiest month (with the highest average wind speed) is February (6.2mph).
The calmest month (with the lowest average wind speed) is July (5mph).

Average humidity in September
Kalaoa, HI

Average humidity in September - Kalaoa, HI
  • Average humidity in September: 76%

The months with the highest relative humidity are June, July and August (77%).
The month with the lowest relative humidity is February (71%).

Average rainfall in September
Kalaoa, HI

Average rainfall in September - Kalaoa, HI
  • Average rainfall in September: 0.75"

The wettest month (with the highest rainfall) is February (0.98").
The driest month (with the least rainfall) is January (0.47").

Average rainfall days in September
Kalaoa, HI

Average rainfall days in September - Kalaoa, HI
  • Average rainfall days in September: 13.4 days

The month with the highest number of rainy days is May (14.4 days).
The month with the least rainy days is February (8.1 days).

Average daylight in September /
Average sunshine in September
Kalaoa, HI

Average daylight in September / Average sunshine in September - Kalaoa, HI
  • Average daylight in September: 12h and 1min

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: 9h and 3min

The month with the most sunshine is June (Average sunshine: 11h and 24min).
The month with the least sunshine is December (Average sunshine: 7h and 24min).

Average sunshine days in September
Kalaoa, HI

Average sunshine days in September - Kalaoa, HI
  • Average sunshine days in September: 8.3 days

The month with the most sunshine days is January (14.5 days).
The month with the least sunshine days is October (6.8 days).

Average UV index in September
Kalaoa, HI

Average UV index in September - Kalaoa, HI
  • Average UV index in September: 6

The months with the highest UV index are January, February, March, April, May, June, July, August, September, October, November and December (UV index 6).
The months with the lowest UV index are January, February, March, April, May, June, July, August, September, October, November and December (UV index 6).

Average cloud cover in September
Kalaoa, HI

Average cloud cover in September - Kalaoa, HI
  • Average cloud cover in September: 18

The months with the most cloud cover are April, May and June (Cloud cover 21).
The month with the least cloud cover is January (Cloud cover 12).

Average visibility in September
Kalaoa, HI

Average visibility in September - Kalaoa, 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).

Kalaoa, Hawaii, USA

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