Very hot in Sep
33°C average high
avg high · 19° at night
25°C+ on almost every day · often 35°C+
Hawaii, USA
Honolulu (Waikiki) weather in September
Is it warm? Yes. September in Honolulu (Waikiki) is hot: afternoons average 32°C and nights 24°C. Most days (80%) peak between 30°C and 32°C.
Hot · average high
32°C
25°C or more on almost every day.
- Average low24°overnight
- Sea27°average, 2022–2025
- Rainy days224 mm in the month
- SkySome cloud32% cloud · 63% clear days
How warm it really gets
Every September afternoon from 2011–2025: 450 days. Most (80%) peaked between 30° and 32°.
September, year by year
The average September high in each year. The warmest, 2019, averaged 33°C; the coolest, 2012, 30°C.
Compared with home
Average September highs. Expect rain on about 2 days (24 mm in a typical month).
- Honolulu (Waikiki)32°
- London21°
- Manchester18°
- Dublin18°
- Cork18°
- Belfast17°
- Glasgow17°
Warmer in September, not much further
Flying times are estimates from Dublin; Honolulu (Waikiki) is about 14h 15m.
Hot in Sep
33°C average high
avg high · 21° at night
25°C+ on almost every day · often 35°C+
Hot in Sep
33°C average high
avg high · 20° at night
25°C+ on almost every day
Air: Copernicus ERA5-Land, 2011–2025, matched to the official averages for Honolulu airport. Sea: Copernicus ERA5, 2022–2025. Rainy days = days with 1 mm of rain or more, as weather stations count them. Clear day = average cloud cover of 30% or less. These are averages of past weather, not a forecast. Methodology