WEATHER · CLIMATE NORMALS · 1991–2020
Honolulu Climate — Averages by Month
What the weather in Honolulu, USaverages across a standard 30-year period. Each month's figure is the 1991–2020 mean temperature and total rainfall from the ERA5 reanalysis — the long-run normal a place settles around, not a forecast for any particular day.
Month-by-month normals
| Month | Avg temperature | Avg rainfall |
|---|---|---|
| January | 22.7 °C | 43.7 mm |
| February | 22.4 °C · coldest | 34.8 mm |
| March | 22.5 °C | 47.1 mm |
| April | 23.0 °C | 19.2 mm |
| May | 23.8 °C | 21.0 mm |
| June | 24.6 °C | 15.5 mm |
| July | 25.1 °C | 14.1 mm |
| August | 25.5 °C | 17.1 mm |
| September | 25.6 °C · warmest | 18.6 mm |
| October | 25.3 °C | 28.6 mm |
| November | 24.5 °C | 47.6 mm |
| December | 23.5 °C | 53.5 mm · wettest |
How to read these numbers
These are reanalysis normals, not readings from a single weather station. They come from the ERA5 0.25° (~25 km) global reanalysis grid, sampled at the grid cell nearest Honolulu — centred at 21.25°N, 157.75°W. A reanalysis blends observations with a physics model onto an even grid, so a coastal or mountain city's cell can read a little cooler, warmer, wetter or drier than the city centre itself. The month-to-month shape — when it's hot, when it rains — is what these normals capture best.
“Normal” means the 1991–2020 average, the current World Meteorological Organization standard period. A normal is what a place tends toward over decades — any single day, month or year can and will depart from it.