September · United States
Best time to visit Kauai in September Weather, crowds & prices
Weather in Kauai in September
Average temperature 27°C, 19 mm of rain, about 30 days with 6+ hours of sunshine and 75% humidity — based on the five most recent complete years of ERA5 data (2021–2025).
September score
9.8/10
Ranked #4 of 12 months
- Avg temp
- 27°C
- Rainfall
- 19 mm
- Humidity
- 75%
- Days with 6h+ sun
- 30
- Crowd Density
- Moderate Crowds
- Average Expenses
- $$$ · Peak Season Rates ($$$)
September in Kauai scores 9.8/10 for beach and coastal travel - an above-average month (#4 of 12). Expect around 27°C, 19 mm of rain, and roughly 30 days with 6+ hours of sunshine this month.
Kauai's Na Pali coast, Waimea canyon and rainforest waterfalls make it Hawaii's greenest island.
September ranks 4th of 12 for Kauai — one of the best windows
Days in September average 27°C (80°F) and humidity near 75% — front-load outdoor plans before the heat builds and treat the middle of the day as indoor time.
With around 19 mm of rain, any showers tend to pass through rather than settle in; about 30 days with 6+ hours of sunshine and 12.1 hours of daylight fill the rest.
On our climate-comfort scale this is one of the strongest months of the year for Kauai at 9.8/10 (4th of 12), just behind June at 9.8/10.
Pack the lightest breathable clothing you own, a hat, and more water than feels necessary.
Expect peak pricing, and crowds are moderate.
Frequently asked
- What is the weather like in Kauai in September?
- In September, Kauai averages 27°C, 19 mm of rain, and about 30 days with 6+ hours of sunshine. Its climate-comfort score is 9.8/10.
- Is September a good time to visit Kauai?
- September earns a 9.8/10 climate-comfort score. Use the year-round chart to weigh the weather against your budget and crowd preferences.
- How much does it rain in Kauai in September?
- Expect about 19 mm of rain in September. Average humidity is 75% and there are about 30 days with 6+ hours of sunshine.
Curated in Kauai
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Kauai, United States. Live activities and tours from GetYourGuide, matched to this destination.