Contents
- Weather in September
- Frequently asked questions
- Average temperature in September
- Average pressure in September
- Average wind speed in September
- Average humidity in September
- Average rainfall in September
- Average rainfall days in September
- Average sea temperature in September
- Average daylight in September
- Average sunshine in September
- Average sunshine days in September
- Average UV index in September
- Average cloud cover in September
- Average visibility in September
Weather in September
Temperature
September, with its average high-temperature of 81.5°F (27.5°C) and an average low-temperature of 75.6°F (24.2°C), holds the record as the warmest month in Honolulu.Heat index
September's heat index is estimated at a hot 86°F (30°C). Ongoing activity coupled with exposure often results in weariness and could induce heat cramps.Take into consideration that the heat index values are calculated for shade and light wind conditions. Heat index values can rise by 15 Fahrenheit (8 Celsius) degrees when in direct sunlight.
Note: The heat index, also known as 'felt air temperature' or 'real feel', is achieved by amalgamating air temperature with the relative humidity readings. Additional elements including metabolic differences, the level of physical activity, and attire have a role in shaping the individual's temperature perception. It is important to note that direct sunlight can intensify the weather impact, potentially raising the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly relevant to babies and toddlers. Children often miss understanding the importance of rest and rehydration. Thirst usually appears late during dehydration - therefore, maintaining hydration, particularly during long physical activities, is essential.
Humidity
The months with the lowest humidity in Honolulu are April, May, September and November, with an average relative humidity of 74%.Rainfall
In Honolulu, Hawaii, in September, during 17.9 rainfall days, 1.22" (31mm) of precipitation is typically accumulated. In Honolulu, during the entire year, the rain falls for 197.2 days and collects up to 14.61" (371mm) of precipitation.Ocean temperature
With an average ocean temperature of 80.4°F (26.9°C), September is the month with the warmest seawater.Note: Water temperature from 77°F (25°C) to 84.2°F (29°C) is considered very warm, making water activities enjoyable for prolonged periods without any uncomfortable sensations.
Daylight
In September, the average length of the day 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 Honolulu, the average sunshine in September is 8.9h.UV index
The months with the highest UV index in Honolulu, Hawaii, are July through September, with an average maximum UV index of 7. A UV Index reading of 6 to 7 represents a high health vulnerability from exposure to the Sun's UV rays for the average person.Note: In September, an average UV index of 7 transforms into the following instructions:
Apply measures and align with sun safety principles. Safeguarding against skin and eye injury is pivotal. Be aware that the sun's UV radiation is strongest between 10 a.m. and 4 p.m. and try to reduce direct sun exposure during this period as much as possible. Using UVA and UVB-protective sunglasses and sun-protective clothing is effective against UV radiation. Stay vigilant! UV rays get a boost in intensity due to sand and water reflections.
Frequently asked questions
What is the hottest time of year in Honolulu?
What is the average September temperature in Honolulu?
What are the least humid months in Honolulu?
What is the average humidity in September in Honolulu?
How many days does it rain in September in Honolulu?
When is the ocean warmest in Honolulu?
How warm is the water in September in Honolulu?
How many hours of daylight does Honolulu have in September?
When is the sunrise / sunset in September in Honolulu?
How many hours of sunshine does Honolulu have in September?
What are the months with the highest UV index in Honolulu?
What is the UV index reading in September in Honolulu?
Average temperature in September
Honolulu, 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
Honolulu, 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
Honolulu, 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
Honolulu, 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
Honolulu, 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
Honolulu, 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
Honolulu, 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
Honolulu, 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 5min
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
Honolulu, 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
Honolulu, 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
Honolulu, 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
Honolulu, 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).
Honolulu, Hawaii, USA
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