September weather forecast
Ewa Beach, HI

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Weather in September

September in Ewa Beach witnesses an exquisite balance between the receding summer and the upcoming fall. The maintained ocean temperature underlines the persistent allure of the beachfront. The weather upholds the summer charm, facilitated by the pleasant temperatures and long beaches. However, the increasing rainfall and shrinking daylight hours subtly hint at the changing season. Meanwhile, the beach town basks in the outstanding Hawaiian climate, savoring the final beats of summer.

Temperature

During August and September, Ewa Beach experiences its highest average temperatures, peaking at 81.5°F (27.5°C).

Heat index

In September, the heat index is computed to be a hot 86°F (30°C). If one sustains activity during exposure, it could lead to a sense of fatigue, with a chance of heat cramps.
Heat index values are typically calculated for conditions of shade and a light breeze. Direct sunlight might lead to a heat index increase by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature' or 'felt air temperature', offers an insight into how hot it feels when we factor in moisture content. Elements such as metabolic variations, pregnancy, and physical exertion can influence one's weather perception. Always consider that direct sunlight exposure might heighten the heat's effects, pushing the heat index up by 15 Fahrenheit (8 Celsius) degrees. Heat index values are largely significant for babies and toddlers. Children usually face more risks than adults as their ability to sweat is less. Additionally, their larger skin surface in relation to their petite bodies and higher heat output due to their activities increases their vulnerability.

Humidity

January, April through June, August through November, with an average relative humidity of 74%, are the least humid months.

Rainfall

In Ewa Beach, in September, during 13.3 rainfall days, 0.83" (21mm) of precipitation is typically accumulated. Throughout the year, there are 172.2 rainfall days, and 12.72" (323mm) of precipitation is accumulated.

Ocean temperature

The month with the warmest seawater is September, with an average ocean temperature of 80.6°F (27°C).
Note: Water temperature ranging from 77°F (25°C) to 84.2°F (29°C) is recognized as warm and pleasant by all, making water activities comfortable and delightful for long durations.

Daylight

In September, the average length of the day is 12h and 15min.
On the first day of the month, sunrise is at 6:15 am and sunset at 6:47 pm. On the last day of September, sunrise is at 6:23 am and sunset at 6:20 pm HST.

Sunshine

In Ewa Beach, the average sunshine in September is 9.3h.

UV index

June through September, with an average maximum UV index of 7, are months with the highest UV index in Ewa Beach. A UV Index reading of 6 to 7 represents a high health risk from exposure to the Sun's UV rays for ordinary individuals.
Note: The daily high UV index of 7 during September translates into the following recommendations:
Incorporate safeguards and honour sun safety principles. Protection from skin and eye damage is obligatory. Between 10 a.m. and 4 p.m., UV radiation is strongest. Make an effort to avoid direct sunlight during this time, remembering that shade structures may not provide full sun protection. For minimizing sun-related eye damage, always choose sunglasses with UVA and UVB coverage. Alert! UV radiation becomes sharper due to reflections from sand and water.
Updated: Aug 17, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What part of the year is the hottest?

Ewa Beach witnesses its peak temperatures during August and September, when the average high-temperature reaches 81.5°F (27.5°C).

What is the average September temperature?

In September, the average high-temperature and low-temperature are 81.5°F (27.5°C) and 76.3°F (24.6°C) respectively. In September, the average heat index (a.k.a. 'feels like', 'apparent temperature'), which represents the influence of relative humidity on air temperature, is computed to be 86°F (30°C).

What are the least humid months?

January, April through June, August through November, with an average relative humidity of 74%, are the least humid months.

What is the average humidity in September?

In Ewa Beach, the average relative humidity in September is 74%.

How much does it rain in September?

In Ewa Beach, in September, during 13.3 rainfall days, 0.83" (21mm) of precipitation is typically accumulated.

What is the month with the warmest ocean?

With an average ocean temperature of 80.6°F (27°C), September is the month with the warmest seawater.

What is the ocean temperature in September?

In Ewa Beach, the average seawater temperature in September is 80.6°F (27°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.

How many hours of daylight does Ewa Beach have in September?

In September, the average day length is 12h and 15min.

When is the sunrise / sunset in September?

In September, on the first day of the month, sunrise is at 6:15 am and sunset at 6:47 pm. On the last day of the month, sunrise is at 6:23 am and sunset at 6:20 pm HST.

How many hours of sunshine does Ewa Beach have in September?

In Ewa Beach, the average sunshine duration in September is 9.3h.

What are the months with the highest UV index?

The months with the highest UV index are June through September, with an average maximum UV index of 7.

What is the UV index intensity in September?

In Ewa Beach, the average daily maximum UV index in September is 7. A UV Index value of 6 to 7 symbolizes a high health threat from unsafe exposure to Sun's UV rays.

Average temperature in September
Ewa Beach, HI

Average temperature in September - Ewa Beach, HI
  • Average high temperature in September: 81.5°F

The warmest months (with the highest average high temperature) are August and September (81.5°F).
The month with the lowest average high temperature is February (74.8°F).

  • Average low temperature in September: 76.3°F

The months with the highest average low temperature are August and September (76.3°F).
The coldest month (with the lowest average low temperature) is February (69.4°F).

Average pressure in September
Ewa Beach, HI

Average pressure in September - Ewa Beach, 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
Ewa Beach, HI

Average wind speed in September - Ewa Beach, HI
  • Average wind speed in September: 9.8mph

The windiest month (with the highest average wind speed) is July (11.9mph).
The calmest months (with the lowest average wind speed) are January and October (9.1mph).

Average humidity in September
Ewa Beach, HI

Average humidity in September - Ewa Beach, HI
  • Average humidity in September: 74%

The month with the highest relative humidity is December (76%).
The months with the lowest relative humidity are January, April, May, June, August, September, October and November (74%).

Average rainfall in September
Ewa Beach, HI

Average rainfall in September - Ewa Beach, HI
  • Average rainfall in September: 0.83"

The wettest month (with the highest rainfall) is March (1.77").
The driest month (with the least rainfall) is July (0.43").

Average rainfall days in September
Ewa Beach, HI

Average rainfall days in September - Ewa Beach, HI
  • Average rainfall days in September: 13.3 days

The month with the highest number of rainy days is March (18.1 days).
The month with the least rainy days is July (11.3 days).

Average sea temperature in September
Ewa Beach, HI

Average sea temperature in September - Ewa Beach, HI
  • Average sea temperature in September: 80.6°F

The best month for swimming (with the highest average sea temperature) is September (80.6°F).
The coldest month (with the lowest average sea temperature) is March (75.7°F).

Average daylight in September /
Average sunshine in September
Ewa Beach, HI

Average daylight in September / Average sunshine in September - Ewa Beach, 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 54min).

  • Average sunshine in September: 9h and 2min

The month with the most sunshine is June (Average sunshine: 11h and 0min).
The month with the least sunshine is November (Average sunshine: 6h and 42min).

Average sunshine days in September
Ewa Beach, HI

Average sunshine days in September - Ewa Beach, HI
  • Average sunshine days in September: 12.2 days

The months with the most sunshine days are July and August (15.3 days).
The month with the least sunshine days is March (6.8 days).

Average UV index in September
Ewa Beach, HI

Average UV index in September - Ewa Beach, HI
  • Average UV index in September: 7

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

Average cloud cover in September
Ewa Beach, HI

Average cloud cover in September - Ewa Beach, HI
  • Average cloud cover in September: 30

The month with the most cloud cover is March (Cloud cover 37).
The month with the least cloud cover is September (Cloud cover 30).

Average visibility in September
Ewa Beach, HI

Average visibility in September - Ewa Beach, 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).

Ewa Beach, Hawaii, USA

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