September weather forecastPearl City, HI
September
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
The warmest period falls in August and September, when the average high-temperature reaches 82°F (27.8°C).Heat index
For most parts of September, the heat index is computed to be a hot 87.8°F (31°C). Long-lasting exposure and activity potentially induce a sense of weariness, with the risk of heat cramps.Heat index values are typically calculated for conditions of shade and a light breeze. Under direct sunshine, the heat index values might be elevated by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature' or 'felt air temperature', arises from combining readings of air temperature and relative moisture content. One's perception of temperature can vary depending on physical activity and individual heat sensitivity, influenced by factors like wind, attire, and metabolic variations. The sun, when shining directly, can have a significant impact on the perceived temperature, increasing the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly relevant to children. Youngsters often neglect the necessity for rest and hydration. Thirst is a sign of advancing dehydration - thus the importance of maintaining hydration, specifically during long-lasting physical activities.
Humidity
April through June and September, with an average relative humidity of 74%, are the least humid months.Rainfall
In Pearl City, in September, during 19.5 rainfall days, 1.46" (37mm) of precipitation is typically accumulated. Throughout the year, there are 208.4 rainfall days, and 16.5" (419mm) of precipitation is accumulated.Ocean temperature
September is the month with the warmest seawater in Pearl City, with an average ocean temperature of 80.4°F (26.9°C).Note: Water temperatures between 77°F (25°C) and 84.2°F (29°C) are regarded as very warm, ensuring all water activities are pleasurable for extended periods without feeling uneasy.
Daylight
In Pearl City, the average length of the day in September 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, in Pearl City, sunrise is at 6:23 am and sunset at 6:20 pm HST.
Sunshine
In September, the average sunshine is 8.4h.UV index
September is the month with the highest UV index in Pearl City, with an average maximum UV index of 7. A UV Index estimate of 6 to 7 represents a high health risk from exposure to the Sun's UV radiation for the average person.Note: The maximum daily UV index of 7 in September interprets into the following recommendations:
Prevent overexposure. Protection from the sun's harmful effects is needed. The time between 10 a.m. and 4 p.m. is when UV radiation is at its peak. Limit exposure to direct sunlight during these hours. Employ a hat with a wide brim for robust protection, cutting UV exposure by half. Notice! The reflection of water and sand increases the UV radiation significantly.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
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).
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).
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).
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%).
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").
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).
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).
Average daylight in September /
Average sunshine in September
Pearl City, HI
- Average daylight in September: 12h and 18min
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 24min
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).
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).
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).
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).
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).
