September weather forecast
Waimanalo Beach, HI

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Weather in September

September, the first month of the autumn in Waimanalo Beach, is still a warm month, with an average temperature varying between 80.6°F (27°C) and 77°F (25°C).

Temperature

Waimanalo Beach's temperatures tend to reach their peak averages in September, with a high of 80.6°F (27°C) and a low of 77°F (25°C).

Heat index

The heat index for September is evaluated at 84.2°F (29°C). If one sustains activity during exposure, it could lead to a sense of fatigue, with a chance of heat cramps.
One should be cognizant that the heat index values are tailored for shaded spots and mild winds. Exposing to direct sunshine may enhance heat index values by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'feels like', is a measure of how hot it feels when the actual air humidity is factored in. The individual's experience of temperature can be shaped by numerous aspects such as metabolic variations, physical exertion, and attire. Take note that direct exposure to the sun can increase the felt temperature, possibly adding 15 Fahrenheit (8 Celsius) degrees to the heat index. Heat index values are particularly important for children. Young kids are often more at risk than adults as they tend to perspire less. Besides, their skin surface is larger relative to their small bodies, and their increased heat output from their active lifestyle compounds their risk.

Humidity

The average relative humidity in September is 75%.

Rainfall

In September, in Waimanalo Beach, the rain falls for 13 days. Throughout September, 0.94" (24mm) of precipitation is accumulated. Throughout the year, in Waimanalo Beach, there are 169.9 rainfall days, and 13.15" (334mm) of precipitation is accumulated.

Ocean temperature

With an average ocean temperature of 80.4°F (26.9°C), September is the month with the warmest seawater.
Note: Ideal surface water temperatures for any water activity fall between 77°F (25°C) and 84.2°F (29°C), offering maximum enjoyment for lengthened periods.

Daylight

In September, the average length of the day in Waimanalo Beach is 12h and 15min.
On the first day of the month, sunrise is at 6:14 am and sunset at 6:46 pm. On the last day of September, in Waimanalo Beach, Hawaii, sunrise is at 6:21 am and sunset at 6:18 pm HST.

Sunshine

The average sunshine in September in Waimanalo Beach is 9.3h.

UV index

The months with the highest UV index are July through October, with an average maximum UV index of 7. A UV Index value of 6 to 7 symbolizes a high health hazard from exposure to the Sun's UV radiation for the average person.
Note: In September, the UV index of 7 transforms into the following advice:
Embrace precautions and observe sun safety norms. Evasion of sunburn is a necessity. From 10 a.m. to 4 p.m., when UV radiation is at its strongest, limit direct exposure to the Sun and note that shade structures may not provide full sun protection. It's wise to wear UVA and UVB-blocking sunglasses when the sun shines brightly. Stay alert! Reflective properties of sand and water amplify the Sun's UV radiation.
Updated: Feb 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What time of the year is the hottest in Waimanalo Beach?

September tends to be the warmest month in Waimanalo Beach, Hawaii, with temperatures averaging a daily high of 80.6°F (27°C) and a low of 77°F (25°C).

What is the average September temperature in Waimanalo Beach?

The average high-temperature, in September, in Waimanalo Beach, is 80.6°F (27°C), while the average low-temperature is 77°F (25°C). The average heat index (a.k.a. 'felt air temperature', 'feels like'), which factors the actual air temperature with the relative humidity, in September is evaluated at 84.2°F (29°C).

What is the average humidity in September in Waimanalo Beach?

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

How much does it rain in Waimanalo Beach in September?

In Waimanalo Beach, Hawaii, in September, during 13 rainfall days, 0.94" (24mm) of precipitation is typically accumulated.

What is the month with the warmest ocean in Waimanalo Beach?

With an average ocean temperature of 80.4°F (26.9°C), September is the month with the warmest seawater in Waimanalo Beach, Hawaii.

How warm is the water in September in Waimanalo Beach?

In September, the average ocean temperature in Waimanalo Beach, Hawaii, is 80.4°F (26.9°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 Waimanalo Beach have in September?

In Waimanalo Beach, Hawaii, the average day length in September is 12h and 15min.

When are sunrise and sunset in September in Waimanalo Beach?

In September, on the first day of the month, sunrise is at 6:14 am and sunset at 6:46 pm. On the last day of the month, sunrise is at 6:21 am and sunset at 6:18 pm HST.

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

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

When is the highest UV index in Waimanalo Beach?

The months with the highest UV index in Waimanalo Beach, Hawaii, are July through October, with an average maximum UV index of 7.

What is the UV index reading in September in Waimanalo Beach?

The average daily maximum UV index in September in Waimanalo Beach is 7. A UV Index estimate of 6 to 7 represents a high health risk from exposure to the Sun's UV radiation.
Average humidity
Average rainfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Waimanalo Beach, HI

Average temperature in September - Waimanalo Beach, HI
  • Average high temperature in September: 80.6°F

The warmest month (with the highest average high temperature) is September (80.6°F).
The month with the lowest average high temperature is February (74.5°F).

  • Average low temperature in September: 77°F

The months with the highest average low temperature are September and October (77°F).
The coldest month (with the lowest average low temperature) is February (70.5°F).

Average pressure in September
Waimanalo Beach, HI

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

Average wind speed in September - Waimanalo Beach, HI
  • Average wind speed in September: 11.9mph

The windiest month (with the highest average wind speed) is July (14.1mph).
The calmest month (with the lowest average wind speed) is January (10.7mph).

Average humidity in September
Waimanalo Beach, HI

Average humidity in September - Waimanalo Beach, HI
  • Average humidity in September: 75%

The months with the highest relative humidity are April, June, July, August and December (76%).
The months with the lowest relative humidity are January and November (74%).

Average rainfall in September
Waimanalo Beach, HI

Average rainfall in September - Waimanalo Beach, HI
  • Average rainfall in September: 0.94"

The wettest month (with the highest rainfall) is March (1.69").
The driest month (with the least rainfall) is July (0.55").

Average rainfall days in September
Waimanalo Beach, HI

Average rainfall days in September - Waimanalo Beach, HI
  • Average rainfall days in September: 13 days

The month with the highest number of rainy days is March (16.9 days).
The month with the least rainy days is June (11.3 days).

Average sea temperature in September
Waimanalo Beach, HI

Average sea temperature in September - Waimanalo Beach, HI
  • Average sea temperature in September: 80.4°F

The best month for swimming (with the highest average sea temperature) is September (80.4°F).
The coldest month (with the lowest average sea temperature) is March (75.7°F).

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

Average daylight in September / Average sunshine in September - Waimanalo 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 12min).
The month with the least sunshine is December (Average sunshine: 6h and 36min).

Average sunshine days in September
Waimanalo Beach, HI

Average sunshine days in September - Waimanalo Beach, HI
  • Average sunshine days in September: 11 days

The month with the most sunshine days is June (13.6 days).
The months with the least sunshine days are March and November (6.6 days).

Average UV index in September
Waimanalo Beach, HI

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

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

Average cloud cover in September
Waimanalo Beach, HI

Average cloud cover in September - Waimanalo Beach, HI
  • Average cloud cover in September: 27

The month with the most cloud cover is March (Cloud cover 36).
The month with the least cloud cover is September (Cloud cover 27).

Average visibility in September
Waimanalo Beach, HI

Average visibility in September - Waimanalo 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).

Waimanalo Beach, Hawaii, USA

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