Weather in Honolulu in September 2025
Average weather
Average temperature in Honolulu in September
Going from a maximum of +32°C during the day to a minimum of +22°C during the night, the temperature in September averages around +30°C.
The average maximum temperature goes up 10% by the end of the month, compared with the beginning of the month, from +30°C to +31°C.
Is Honolulu warm or cold in September?
Honolulu is typically warm in September.
Maximum temperatures go up compared to the previous month from +30°C to +30°C. The minimum temperature also goes up from +24°C to +24°C.
It’s generally warm, but pack a long-sleeve shirt for evenings.
September is one of the warmest months in Honolulu, here is the comparison with other months:
Water temperature in Honolulu in September
Water in Honolulu in September is Warm. It varies from +26°C to +28°C, with an average of +27°C. This is almost similar to the air temperature, which averages +30°C.
The water temperature in September is one of the warmest of the entire year:
Can you swim in Honolulu in September?
Climate in Honolulu in September
| August | September | October | ||||
|---|---|---|---|---|---|---|
| Avg. temperature | ||||||
| +30°C | +30°C | +30°C | ||||
| Min. temperature | ||||||
| +20°C | +20°C | +15°C | ||||
| Max. temperature | ||||||
| +33°C | +34°C | +33°C | ||||
| Rainfall | ||||||
| 19 mm | 26 mm | 50 mm | ||||
| Wind | ||||||
| 5 m/s | 4 m/s | 4 m/s | ||||
| Avg. water temperature | ||||||
| +26°C | +27°C | +26°C | ||||
| Humidity | ||||||
| 68% | 69% | 70% | ||||
| Air pressure | ||||||
| 1015 HPa | 1014 HPa | 1014 HPa | ||||
| Sunny days | ||||||
| 5 | 5 | 5 | ||||
| Cloudy days | ||||||
| 16 | 12 | 12 | ||||
| Rainy days | ||||||
| 10 | 12 | 13 | ||||
| Snowy days | ||||||
| 0 | 0 | 0 | ||||
September weather is still as good as in August. The temperature levels stay the same in the area of +30°C for average maximum temperature during the day. Prepare for more rain. Average rainfall goes from 19 mm to 26 mm. Humidity rises from 68% to 69%. Winds are calmer in comparison to August, going down from 5 m/s to 4 m/s on average. The amount of sunny days stay about the same, averaging 5 sunny days during the month.
October brings much the same weather, it remains good.
Wind
The average wind speed is 5 m/s getting up to 6 m/s which is a medium breeze. You can feel it, especially getting out of the water.
The average wind speed in Honolulu is gradually increasing during September, going from 6 m/s to 6 m/s over the course of the month.
Rain
How was the weather last September in Honolulu?
Climate Change over Years
The climate in Honolulu in September has not changed much over the last 43 years.
The average temperature was the lowest in 1983 (+25°C) and the highest in 1988 (+29°C). The driest year was 1983 with only 113 mm of rainfall, and the wettest year was 1982 with 1336 mm.
FAQ
Is September a good time to visit Honolulu?
Can you sunbathe in Honolulu in September?
Can you swim in Honolulu in September?
Is Honolulu rainy in September?
Is it sunny in Honolulu in September?
Other cities in USA
Monthly weather in Honolulu
Source of the data
For this page, we’ve looked at the typical weather in Honolulu, based on historical hourly weather data from January 1, 1979, to December 31, 2023.
For past dates, we show actual recorded data at the location at that time. Forecasts are based on recorded weather during that day of the year, averaged over the total years for which we have records (unless stated otherwise). The daily temperature is the highest recorded temperature in the shadow during that day.