September weather forecastHanalei, HI
September
Weather in September
September is known in Hanalei for signaling the outset of autumn marking a decrease in both soaring temperatures and high rainfall levels from August. Slightly cooler temperatures and reduced rainfall, coupled with consistent sea temperatures at 81°F (27.2°C), render September conducive for beach activities. Fireworks in the sky are replaced with milder weather conditions leading in the more-balanced month of October.Temperature
September stands out as Hanalei's warmest month, with temperatures ranging between an average high of 79.7°F (26.5°C) and a low of 75.9°F (24.4°C).Humidity
In September, the average relative humidity is 76%.Rainfall
In Hanalei, during September, the rain falls for 18.7 days and regularly aggregates up to 1.54" (39mm) of precipitation. In Hanalei, during the entire year, the rain falls for 218.4 days and collects up to 22.13" (562mm) of precipitation.Ocean temperature
September and October, with an average ocean temperature of 80.6°F (27°C), are months with the warmest seawater.Note: For engaging in water activities including swimming and diving, temperatures from 77°F (25°C) to 84.2°F (29°C) are perceived as perfect, providing pleasure for extended durations.
Daylight
In Hanalei, the average length of the day in September is 12h and 16min.On the first day of the month, sunrise is at 6:21 am and sunset at 6:54 pm. On the last day of September, sunrise is at 6:29 am and sunset at 6:25 pm HST.
Sunshine
The average sunshine in September is 8.7h.UV index
With an average maximum UV index of 7, September is the month with the highest UV index. A UV Index estimate of 6 to 7 represents a high health risk from unprotected exposure to Sun's UV rays for average individuals.Note: In September, the maximum UV index of 7 transforms into these recommendations:
Implement preventive steps and embrace sun safety standards. Protection from skin and eye distress is compulsory. Minimize exposure to direct sunlight and seek shade from 10 a.m. to 4 p.m., when UV radiation is most intense, but remember that shade structures may not offer complete protection. On days when the sun blazes, arm yourself with sunglasses that block UVA and UVB radiation. Beware! The strength of the UV rays is significantly increased by the reflection of the water and sand.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Hanalei, HI
- Average high temperature in September: 79.7°F
The warmest month (with the highest average high temperature) is September (79.7°F).
The months with the lowest average high temperature are February and March (73.2°F).
- Average low temperature in September: 75.9°F
The month with the highest average low temperature is September (75.9°F).
The coldest month (with the lowest average low temperature) is February (68.5°F).
Average pressure in September
Hanalei, HI
- Average pressure in September: 29.98"Hg
The month with the highest atmospheric pressure is April (30.07"Hg).
The months with the lowest atmospheric pressure are September and October (29.98"Hg).
Average wind speed in September
Hanalei, HI
- Average wind speed in September: 11.1mph
The windiest month (with the highest average wind speed) is July (12.3mph).
The calmest month (with the lowest average wind speed) is January (10mph).
Average humidity in September
Hanalei, HI
- Average humidity in September: 76%
The months with the highest relative humidity are June, July, August, October and December (77%).
The month with the lowest relative humidity is January (75%).
Average rainfall in September
Hanalei, HI
- Average rainfall in September: 1.54"
The wettest month (with the highest rainfall) is March (2.52").
The driest month (with the least rainfall) is April (1.3").
Average rainfall days in September
Hanalei, HI
- Average rainfall days in September: 18.7 days
The month with the highest number of rainy days is August (21.1 days).
The month with the least rainy days is January (12.5 days).
Average sea temperature in September
Hanalei, HI
- Average sea temperature in September: 81°F
The best months for swimming (with the highest average sea temperature) are September and October (81°F).
The coldest months (with the lowest average sea temperature) are January, February, March and April (75°F).
Average daylight in September /
Average sunshine in September
Hanalei, HI
- Average daylight in September: 12h and 18min
The month with the longest days is June (Average daylight: 13h and 30min).
The month with the shortest days is December (Average daylight: 10h and 48min).
- Average sunshine in September: 8h and 42min
The month with the most sunshine is June (Average sunshine: 9h and 42min).
The month with the least sunshine is November (Average sunshine: 6h and 12min).
Average sunshine days in September
Hanalei, HI
- Average sunshine days in September: 5.3 days
The month with the most sunshine days is January (12.8 days).
The month with the least sunshine days is August (2.9 days).
Average UV index in September
Hanalei, 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
Hanalei, HI
- Average cloud cover in September: 38
The month with the most cloud cover is March (Cloud cover 47).
The months with the least cloud cover are January and September (Cloud cover 38).
Average visibility in September
Hanalei, 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).
