Hawaii, USA
Long-term weather forecast
Long-term weather forecast

September weather forecast and climate
Halawa, HI

  • Average high temperature in September: 82°F

Warmest months (with the highest average high temperature) are July, August, September and October (82°F).
Months with the lowest average high temperature are January, February and March (77°F).

  • Average low temperature in September: 66°F

The month with the highest average low temperature is August (68°F).
Coldest months (with the lowest average low temperature) are January, February and March (61°F).

  • Average rainfall in September: 2"

The wettest month (with the highest rainfall) is January (7.4").
The driest month (with the lowest rainfall) is June (1.9").

  • Average rainfall days in September: 7 days

Months with the highest number of rainy days are January, March, April and December (12 days).
Months with the lowest number of rainy days are June and September (7 days).

  • Average sea temperature in September: 81°F

The best month for swimming (with the highest average sea temperature) is September (81°F).
Coldest months (with the lowest average sea temperature) are January, February, March and April (75°F).

  • Average daylight in September: 13h

The month with the longest days is June (Average daylight: 14.2h).
The month with shortest days is December (Average daylight: 11.7h).

  • Average sunshine in September: 9h

Months with most sunshine are May, June, July, August and September (Average sunshine: 9h).
Months with least sunshine are January, February, November and December (Average sunshine: 7).

  • Average UV index in September: 11

Months with the highest UV index are June, July and August (UV index 12).
The month with the lowest UV index is December (UV index 6).