Koloa Weather in September
September in Koloa sees daytime temperatures around 28°C (82°F) and lows of 24°C (75°F) at night. The perfect weather makes it a good time to visit.
Rainfall in Koloa in September
Typically, you can expect about 16 days of rain this month, with 46 mm (1.8 in) on average. Rain is frequent but mostly light this month, with brief showers more common than heavy downpours.
Temperature in Koloa in September
If you're visiting Koloa in September, expect perfect temperatures with highs of 28°C (82°F) and overnight lows of 24°C (75°F). The days can feel warmer than the evenings, so packing for both parts of the day is a good idea. With lows around 24°C (75°F), the nights are warm enough that a sheet is usually all you need for bedding. This is typically the warmest month of the year, so light summer clothing is a good idea.
Sunshine in Koloa in September
With approximately 242 hours of sunshine, the days are filled with clear skies. It makes it a perfect month for being outside.
Wind Speed in Koloa in September
September sees wind speeds averaging 4 m/s (8 knots). You'll experience variable conditions with moderate winds that create small waves on water and keep branches moving. Conditions range from light winds to moderate breezes throughout the month.
Average water temperature in September
At 27°C (81°F), the water is warm and comfortable for swimming. Most people find this temperature ideal for spending longer periods in the water.For more travel ideas, our weather planner can help you explore destinations around the world.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit the United States of America, check out our Koloa's climate page.
Koloa Temperature in September
Min Temperature
24°C (75°F)
Max Temperature
28°C (82°F)
Water Temperature
27°C (81°F) *
Chance of Rain
52%
Precipitation
46 mm (1.8 in)
Rainy days
16 days
Humidity
74% *
Windspeed
4 m/s (8 knots) *
Sunshine
242 hours *
Percentage Sunshine
66% *
Daily Historical Temperatures
50-year average (1976-2025)
Based on our historical records, temperatures in Koloa typically stay consistent throughout September, with daily highs averaging around 28°C (82°F). Nights are warm, with lows around 24°C (75°F).
Average temperatures in September
Daily Historical Precipitation
50-year average (1976-2025)
Average daily rainfall for each day of the month based on long-term records.
Average precipitation in September
Historical weather for Koloa in September
Browse day-by-day weather records for Koloa spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.
Koloa historical weather extremes in September
The extremes listed below come from historical weather data collected in Koloa from 1976 through 2025.
- On September 4, 2019, temperatures climbed to 33°C (91°F), marking the warmest September day on record.
- The coldest September day was on September 7, 1996, with a maximum of 26°C (79°F).
- Nighttime temperatures dropped to 18°C (64°F) on September 17, 1981, marking the coldest September night on record.
Best Places in the United States of America in September
Find out more about the weather in the United States of America and which places have the best travel conditions in this month. See all of the United States of America in September →
perfect weather
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tolerable
unpleasant
poor
What to Wear in Koloa in September
Warm temperatures in September make for comfortable sightseeing weather. Pack breathable fabrics like cotton shirts, knee-length shorts or skirts, and comfortable walking shoes. A thin long sleeve for indoor spaces is handy. Rain gear is recommended, you can expect wet weather on multiple days. The water temperature sits at about 27°C (81°F), making it perfect for swimming and water activities. Don't forget to pack your favorite swimwear and perhaps some snorkel gear. You'll definitely want to pack sunglasses and sunscreen. There will be plenty of bright sunshine this month.What To Do in Koloa in September
We rated the following activities from 1 (least suitable) to 10 (best) to do.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit the United States of America, check out our Koloa's climate page.
Temperature Rainfall Sunshine Humidity Wind Speed Water Temp
See the full Koloa climate overview or explore weather in the United States of America.
