September weather forecast
Pearl City, HI

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Weather in September

As summer winds down, September presents a cooler but still warm climate. The sea remains at its warmest for the year at 80.4°F (26.9°C), welcoming visitors for various water activities. Pearl City’s characteristic comfortable weather persists, nourished by an almost constant level of humidity. Despite the retreat of summer, the month brings abundant sunshine. Although rainfall shows a small increase from August, it does little to dampen the mood of this enchanting city.

Temperature

Pearl City's highest average temperatures are recorded in August and September, reaching a high of 82°F (27.8°C).

Heat index

September's average heat index is evaluated at a tropical 87.8°F (31°C). If activity and exposure persist, they could induce fatigue, leading to possible heat cramps.
Heat index readings emphasize conditions of light breezes and shaded spots. In the presence of direct sunshine, the heat index could be augmented by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature' or 'apparent temperature', integrates the air's temperature and its humidity to showcase the felt temperature by people. The individual's experience of temperature can be shaped by numerous aspects such as metabolic variations, physical exertion, and attire. In the direct sunlight, the weather's impact can be amplified, possibly boosting the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially vital to children. Young people are generally more susceptible than adults because they perspire less. Furthermore, their proportionally larger skin surface to their petite bodies and the increased heat output from their actions add to the risk.

Humidity

April through June and September, with an average relative humidity of 74%, are the least humid months.

Rainfall

In Pearl City, Hawaii, in September, during 19.5 rainfall days, 1.46" (37mm) of precipitation is typically accumulated. Throughout the year, in Pearl City, there are 208.4 rainfall days, and 16.5" (419mm) 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: Water activities including swimming and diving are pleasurable in temperatures between 77°F (25°C) and 84.2°F (29°C), ensuring comfort and enjoyment for extended time frames.

Daylight

In Pearl City, the average length of the day in September is 12h and 15min.
On the first day of September in Pearl City, Hawaii, 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.

Sunshine

In September, the average sunshine in Pearl City is 8.4h.

UV index

The month with the highest UV index in Pearl City is September, with an average maximum UV index of 7. A UV Index reading of 6 to 7 represents a high threat to health from exposure to the Sun's UV radiation for the ordinary person.
Note: In September, the maximum UV index of 7 suggests this advice:
Implement preventive steps and embrace sun safety standards. Protection from skin and eye distress is compulsory. Stay out of direct sunlight and seek shade between 10 a.m. and 4 p.m., when UV radiation is strongest, but remember that shade devices may not offer full sun protection. Wearing sunglasses with both UVA and UVB protection effectively reduces sun-induced eye damage. Attention! The combination of sand and water reflections enhances UV ray intensity.
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Frequently asked questions

What time of the year is the hottest in Pearl City?

Pearl City's temperature peaks during August and September, with an average high-temperature of 82°F (27.8°C).

What are September temperatures in Pearl City?

In September, in Pearl City, the average high-temperature is 82°F (27.8°C), and the average low-temperature is 75°F (23.9°C). The average heat index (a.k.a. 'apparent temperature', 'felt air temperature'), which takes the relative humidity and factors it into the air temperature reading, in September is evaluated at 87.8°F (31°C).

What is the least humid month in Pearl City?

April through June and September, with an average relative humidity of 74%, are the least humid months in Pearl City.

What is the average humidity in September in Pearl City?

In September, the average relative humidity in Pearl City, Hawaii, is 74%.

How much does it rain in Pearl City in September?

In Pearl City, during September, the rain falls for 19.5 days and regularly aggregates up to 1.46" (37mm) of precipitation.

What month is the ocean warmest in Pearl City?

September is the month with the warmest seawater in Pearl City, with an average ocean temperature of 80.4°F (26.9°C).

How warm is the water in September in Pearl City?

In Pearl City, Hawaii, the average seawater temperature in September is 80.4°F (26.9°C). For swimming, diving, and other water activities, temperatures between 77°F (25°C) and 84.2°F (29°C) are perceived as very enjoyable and pleasurable for prolonged periods without feeling uncomfortable.

How many hours of daylight does Pearl City have in September?

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

When are sunrise and sunset in September in Pearl City?

On the first day of September, 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 Pearl City have in September?

The average sunshine duration in September is 8.4h.

When is the highest UV index in Pearl City?

The month with the highest UV index in Pearl City is September, with an average maximum UV index of 7.

How high is the UV index in September in Pearl City?

The average daily maximum UV index in September is 7. A UV Index value of 6 to 7 symbolizes a high hazard to health 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
Pearl City, HI

Average temperature in September - Pearl City, HI
  • Average high temperature in September: 82°F

The warmest months (with the highest average high temperature) are August and September (82°F).
The months with the lowest average high temperature are February and March (75.4°F).

  • Average low temperature in September: 75°F

The month with the highest average low temperature is September (75°F).
The coldest month (with the lowest average low temperature) is February (68°F).

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Average pressure in September
Pearl City, HI

Average pressure in September - Pearl City, 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).

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Average wind speed in September
Pearl City, HI

Average wind speed in September - Pearl City, HI
  • Average wind speed in September: 9.3mph

The windiest month (with the highest average wind speed) is July (11.3mph).
The calmest month (with the lowest average wind speed) is January (8.4mph).

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Average humidity in September
Pearl City, HI

Average humidity in September - Pearl City, HI
  • Average humidity in September: 74%

The months with the highest relative humidity are February and December (76%).
The months with the lowest relative humidity are April, May, June and September (74%).

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Average rainfall in September
Pearl City, HI

Average rainfall in September - Pearl City, HI
  • Average rainfall in September: 1.46"

The wettest month (with the highest rainfall) is October (2.09").
The driest month (with the least rainfall) is July (0.71").

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Average rainfall days in September
Pearl City, HI

Average rainfall days in September - Pearl City, HI
  • Average rainfall days in September: 19.5 days

The month with the highest number of rainy days is March (20 days).
The month with the least rainy days is January (13.5 days).

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Average sea temperature in September
Pearl City, HI

Average sea temperature in September - Pearl City, 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).

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Average daylight in September /
Average sunshine in September
Pearl City, HI

Average daylight in September / Average sunshine in September - Pearl City, 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: 8h and 2min

The month with the most sunshine is June (Average sunshine: 9h and 54min).
The months with the least sunshine are November and December (Average sunshine: 6h and 18min).

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Average sunshine days in September
Pearl City, HI

Average sunshine days in September - Pearl City, HI
  • Average sunshine days in September: 6.5 days

The month with the most sunshine days is January (12.3 days).
The month with the least sunshine days is November (6.2 days).

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Average UV index in September
Pearl City, HI

Average UV index in September - Pearl City, HI
  • Average UV index in September: 7

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

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Average cloud cover in September
Pearl City, HI

Average cloud cover in September - Pearl City, HI
  • Average cloud cover in September: 38

The month with the most cloud cover is March (Cloud cover 44).
The month with the least cloud cover is January (Cloud cover 36).

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Average visibility in September
Pearl City, HI

Average visibility in September - Pearl City, 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).

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Pearl City, Hawaii, USA

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