September · Greece
Best time to visit Kos Island in September Weather, crowds & prices
Weather in Kos Island in September
Average temperature 26°C, 27 mm of rain, about 26 days with 6+ hours of sunshine and 63% humidity — based on the five most recent complete years of ERA5 data (2021–2025).
September score
10.0/10
Ranked #4 of 12 months
- Avg temp
- 26°C
- Rainfall
- 27 mm
- Humidity
- 63%
- Days with 6h+ sun
- 26
- Crowd Density
- Moderate Crowds
- Average Expenses
- $$$ · Peak Season Rates ($$$)
September in Kos Island scores 10.0/10 for beach and coastal travel - an above-average month (#4 of 12). Expect around 26°C, 27 mm of rain, and roughly 26 days with 6+ hours of sunshine this month.
Kos mixes sandy beaches and cycling paths with the ruins of Hippocrates' ancient healing centre.
September ranks 4th of 12 for Kos Island — one of the best windows
Days in September average 26°C (79°F) — front-load outdoor plans before the heat builds and treat the middle of the day as indoor time.
With around 27 mm of rain, any showers tend to pass through rather than settle in; about 26 days with 6+ hours of sunshine and 12.2 hours of daylight fill the rest.
On our climate-comfort scale this is one of the strongest months of the year for Kos Island at 10/10 (4th of 12), just behind June at 10/10.
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 Kos Island in September?
- In September, Kos Island averages 26°C, 27 mm of rain, and about 26 days with 6+ hours of sunshine. Its climate-comfort score is 10.0/10.
- Is September a good time to visit Kos Island?
- September earns a 10.0/10 climate-comfort score. Use the year-round chart to weigh the weather against your budget and crowd preferences.
- How much does it rain in Kos Island in September?
- Expect about 27 mm of rain in September. Average humidity is 63% and there are about 26 days with 6+ hours of sunshine.
Curated in Kos Island
Tickets & experiences
Things to do in Kos Island
Kos Island, Greece. Live activities and tours from GetYourGuide, matched to this destination.