September weather forecastAiea, HI
September
Weather in September
September carries the vestiges of summer into Aiea; the sun continues to be generous while rainfall picks up a sporadic tempo. The sea remains inviting, its familiar warmth undiminished, and the beaches retain their vibrancy. The amount of rainfall in this month increases to 1.22" (31mm), a mark-up from previous months. Gradually, the town moves into an implied preparatory mode, eagerly anticipating the mildness of the Hawaiian winter.Temperature
September, characterized by an average high temperature of 81.5°F (27.5°C) and a low temperature of 75.6°F (24.2°C), is generally the warmest month.Heat index
The heat index for September is computed to be a tropical 86°F (30°C). Exhaustion might be the outcome of enduring exposure and continuous activity, with a risk of heat cramps.Know that the heat index computations account for shaded terrains and slight winds. Exposure to direct sunshine can increase heat index values by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'feels like' or 'felt air temperature', is an amalgamation of air temperature and humidity to express the equivalent perceived temperature. Depending on the activity and the individual's heat perception, which may vary due to factors including wind, clothing, and metabolic variations, this effect remains subjective. One should be aware that direct sunshine can amplify the perceived temperature, raising the heat index by as much as 15 Fahrenheit (8 Celsius) degrees. Heat index values are highly important for children. Young ones often ignore the need to take a break and drink fluids. Thirst is a late-stage symptom of dehydration - hence, maintaining hydration, particularly during extended physical activities, is crucial.
Humidity
April, May, September and November, with an average relative humidity of 74%, are the least humid months.Rainfall
In September, the rain falls for 17.9 days. Throughout September, 1.22" (31mm) of precipitation is accumulated. In Aiea, during the entire year, the rain falls for 197.2 days and collects up to 14.61" (371mm) of precipitation.Ocean temperature
September is the month with the warmest seawater, with an average ocean temperature of 80.4°F (26.9°C).Note: For any water activity, temperatures between 77°F (25°C) and 84.2°F (29°C) are deemed excellent and extremely satisfying for enduring periods.
Daylight
The average length of the day in September is 12h and 15min.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 6:22 am and sunset at 6:19 pm HST.
Sunshine
In September, the average sunshine is 8.9h.UV index
July through September, with an average maximum UV index of 7, are months with the highest UV index. A UV Index estimate of 6 to 7 represents a high health vulnerability from unsafe exposure to UV radiation for the ordinary person.Note: A daily maximum UV index of 7 in September translates into the following instructions:
Uphold preventive measures and conform to sun safety guidelines. Defending against skin and eye harm is crucial. Stay in the shade and limit sun exposure from 10 a.m. to 4 p.m., when UV radiation is most potent. Keep in mind that shade structures like parasols or canopies do not offer full protection. Sunglasses providing both UVA and UVB protection are non-negotiable on sunlit days. Take caution! The UV rays from the Sun gain strength from sand and water reflections.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Aiea, HI
- Average high temperature in September: 81.5°F
The warmest month (with the highest average high temperature) is September (81.5°F).
The months with the lowest average high temperature are February and March (75°F).
- Average low temperature in September: 75.6°F
The month with the highest average low temperature is August (75.7°F).
The coldest month (with the lowest average low temperature) is February (69.1°F).
Average pressure in September
Aiea, 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
Aiea, HI
- Average wind speed in September: 9.9mph
The windiest month (with the highest average wind speed) is July (12.1mph).
The calmest month (with the lowest average wind speed) is January (9mph).
Average humidity in September
Aiea, 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, September and November (74%).
Average rainfall in September
Aiea, HI
- Average rainfall in September: 1.22"
The wettest months (with the highest rainfall) are March and October (1.81").
The driest month (with the least rainfall) is July (0.67").
Average rainfall days in September
Aiea, HI
- Average rainfall days in September: 17.9 days
The months with the highest number of rainy days are March and October (18 days).
The month with the least rainy days is January (12.6 days).
Average sea temperature in September
Aiea, 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
Aiea, 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 54min
The month with the most sunshine is June (Average sunshine: 10h and 48min).
The months with the least sunshine are November and December (Average sunshine: 6h and 30min).
Average sunshine days in September
Aiea, HI
- Average sunshine days in September: 6.9 days
The month with the most sunshine days is January (12.8 days).
The month with the least sunshine days is October (6.3 days).
Average UV index in September
Aiea, 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
Aiea, HI
- Average cloud cover in September: 33
The month with the most cloud cover is March (Cloud cover 40).
The months with the least cloud cover are January and September (Cloud cover 33).
Average visibility in September
Aiea, 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).
