September weather forecast
Kaaawa, HI

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Weather in September

The first month of the autumn, September, is also a moderately hot month in Kaaawa, Hawaii, with temperature in the range of an average high of 81°F (27.2°C) and an average low of 76.3°F (24.6°C).

Temperature

August and September bring Kaaawa's highest average temperatures, reaching a high of 81°F (27.2°C).

Heat index

The heat index for September is estimated at a hot 86°F (30°C). With extended exposure and activity, one might feel exhausted and experience heat cramps.
Data suggests that the heat index is set for environments in shade and with a light wind. Direct sunlight can potentially boost the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'feels like' or 'real feel', is a measure that combines air temperature and relative humidity into a single value that indicates how hot the weather feels. Elements such as metabolic variations, pregnancy, and physical exertion can shape one's weather perception. Direct sun rays have a notable impact on perceived temperature, which can raise the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are extremely vital to babies and toddlers. Children often lack awareness of the importance of taking breaks and rehydrating. The feeling of thirst is a late indication of dehydration, so maintaining hydration, especially during long periods of physical activity, is critical.

Humidity

January, May, June, September and November, with an average relative humidity of 75%, are the least humid months.

Rainfall

In Kaaawa, in September, it is raining for 14.5 days, with typically 1.1" (28mm) of accumulated precipitation. Throughout the year, in Kaaawa, Hawaii, there are 187.1 rainfall days, and 15.83" (402mm) of precipitation is accumulated.

Ocean temperature

September is the month with the warmest seawater, with an average ocean temperature of 80.1°F (26.7°C).
Note: For engaging in any water activities, temperatures from 77°F (25°C) to 84.2°F (29°C) are viewed as outstanding and exceptionally pleasing for prolonged durations.

Daylight

In Kaaawa, the average length of the day in September is 12h and 16min.
On the first day of September in Kaaawa, sunrise is at 6:14 am and sunset at 6:47 pm. On the last day of the month, sunrise is at 6:22 am and sunset at 6:19 pm HST.

Sunshine

In September, the average sunshine is 9h.

UV index

The months with the highest UV index are July through September, with an average maximum UV index of 7. A UV Index of 6 to 7 symbolizes a high health risk from unsafe exposure to UV radiation for the ordinary person.
Note: The UV index of 7 in September translates into these instructions:
Implement precautions and maintain sun safety methods. Avoidance of sunburn is demanded. The hours from 10 a.m. to 4 p.m. have the most intense UV radiation. As much as possible, limit direct sun exposure during this period. Sun protection is enhanced with clothing that boasts a tight weave yet offers a loose fit. Warning! Sand and water reflections boost the intensity of UV exposure.

Frequently asked questions

What is the hottest time of year in Kaaawa?

Warmest months are August and September, with an average high-temperature of 81°F (27.2°C).

What are the temperatures in September?

In September, in Kaaawa, the average high-temperature is 81°F (27.2°C), and the average low-temperature is 76.3°F (24.6°C). In September, the average heat index (a.k.a. 'feels like', 'felt air temperature'), which combines air temperature and relative humidity, is estimated at 86°F (30°C).

What is the least humid month?

January, May, June, September and November, with an average relative humidity of 75%, are the least humid months.

What is the average humidity in September?

In Kaaawa, the average relative humidity in September is 75%.

How many days does it rain in September?

In Kaaawa, in September, during 14.5 rainfall days, 1.1" (28mm) of precipitation is typically accumulated.

When is the ocean warmest?

The month with the warmest seawater is September, with an average ocean temperature of 80.1°F (26.7°C).

How warm is the water in September in Kaaawa?

In Kaaawa, the average seawater temperature in September is 80.1°F (26.7°C). For any water activity, surface water temperatures between 77°F (25°C) and 84.2°F (29°C) are considered as excellent and extremely pleasant for lengthened periods.

What is the average length of the day in September?

The average day length in September is 12h and 16min.

What time are sunrise and sunset in September?

In September, on the first day of the month, sunrise is at 6:14 am and sunset at 6:47 pm. On the last day of the month, sunrise is at 6:22 am and sunset at 6:19 pm HST.

How long on average sun shines in September?

The average sunshine duration in September is 9h.

What is the month with the highest UV index?

July through September, with an average maximum UV index of 7, are months with the highest UV index in Kaaawa.

What is the UV index reading in September?

In September, the average daily maximum UV index is 7. A UV Index estimate of 6 to 7 represents a high health threat from exposure to Sun's UV rays.

Average temperature in September
Kaaawa, HI

Average temperature in September - Kaaawa, HI
  • Average high temperature in September: 81°F

The warmest months (with the highest average high temperature) are August and September (81°F).
The month with the lowest average high temperature is February (74.3°F).

  • Average low temperature in September: 76.3°F

The month with the highest average low temperature is August (76.6°F).
The coldest month (with the lowest average low temperature) is February (69.6°F).

Average pressure in September
Kaaawa, HI

Average pressure in September - Kaaawa, HI
  • Average pressure in September: 29.97"Hg

The month with the highest atmospheric pressure is April (30.06"Hg).
The months with the lowest atmospheric pressure are September and October (29.97"Hg).

Average wind speed in September
Kaaawa, HI

Average wind speed in September - Kaaawa, HI
  • Average wind speed in September: 11.4mph

The windiest month (with the highest average wind speed) is July (13.5mph).
The calmest month (with the lowest average wind speed) is January (10.3mph).

Average humidity in September
Kaaawa, HI

Average humidity in September - Kaaawa, HI
  • Average humidity in September: 75%

The months with the highest relative humidity are February, March, April, July, August, October and December (76%).
The months with the lowest relative humidity are January, May, June, September and November (75%).

Average rainfall in September
Kaaawa, HI

Average rainfall in September - Kaaawa, HI
  • Average rainfall in September: 1.1"

The wettest month (with the highest rainfall) is March (2.01").
The driest month (with the least rainfall) is July (0.71").

Average rainfall days in September
Kaaawa, HI

Average rainfall days in September - Kaaawa, HI
  • Average rainfall days in September: 14.5 days

The month with the highest number of rainy days is March (18.3 days).
The month with the least rainy days is June (13.5 days).

Average sea temperature in September
Kaaawa, HI

Average sea temperature in September - Kaaawa, HI
  • Average sea temperature in September: 80.1°F

The best month for swimming (with the highest average sea temperature) is September (80.1°F).
The coldest month (with the lowest average sea temperature) is March (75°F).

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

Average daylight in September / Average sunshine in September - Kaaawa, HI
  • Average daylight in September: 12h and 2min

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 48min).

  • Average sunshine in September: 9h and 0min

The month with the most sunshine is June (Average sunshine: 10h and 42min).
The month with the least sunshine is December (Average sunshine: 6h and 18min).

Average sunshine days in September
Kaaawa, HI

Average sunshine days in September - Kaaawa, HI
  • Average sunshine days in September: 11.2 days

The month with the most sunshine days is June (12.2 days).
The month with the least sunshine days is April (6.5 days).

Average UV index in September
Kaaawa, HI

Average UV index in September - Kaaawa, HI
  • Average UV index in September: 7

The months with the highest UV index are July, August and September (UV index 7).
The months with the lowest UV index are January, February, March, April, May, June, October, November and December (UV index 6).

Average cloud cover in September
Kaaawa, HI

Average cloud cover in September - Kaaawa, HI
  • Average cloud cover in September: 32

The month with the most cloud cover is March (Cloud cover 41).
The month with the least cloud cover is September (Cloud cover 32).

Average visibility in September
Kaaawa, HI

Average visibility in September - Kaaawa, 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).

Kaaawa, Hawaii, USA

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