Sea temperature in Kos in September
The sea around Kos averages 26°C in September, usually between 24°C and 27°C. That is warm enough for most people to swim comfortably.
Average26°CWarm
Usual range24°C–27°C80% of readings
vs August−0.5°cooler
vs October−1.8°cooler next month
Through the year
Monthly averages 2023–2025. Water at 22°C or warmer: June–November.
September in recent years
| 2023 | 26°C |
|---|---|
| 2024 | 25°C |
| 2025 | 26°C |
Nearby in September
Beaches in Kos
15 of 16 beaches have an Excellent EU water-quality grade. See which ones are calm today.