Kos weather by month: heat, rain and sea temperature
A monthly weather table for Kos, what to expect in spring and autumn, and why the island works well in October.
- June to September: 28–31°C, almost no rain, sea 22–24°C.
- October is still pleasant: up to 24°C and a sea of about 22°C.
- December and January are the wettest, about 12 rain days.
Kos has one of the longest seasons in Greece. For warm sea without peak heat, aim for late May, June or September–October.
Kos weather by month
Kos sits in the Dodecanese close to the Turkish coast, so its climate is warm and fairly dry. The table uses long-term averages (1991–2020) from Climates to Travel, rounded to whole degrees.
| Month | Low | High | Rain days | Sea |
|---|---|---|---|---|
| January | 9° | 14° | 12 | 17° |
| February | 9° | 14° | 10 | 16° |
| March | 10° | 16° | 9 | 16° |
| April | 13° | 19° | 7 | 17° |
| May | 17° | 24° | 5 | 19° |
| June | 21° | 29° | 3 | 22° |
| July | 23° | 31° | 3 | 24° |
| August | 23° | 31° | 3 | 25° |
| September | 21° | 28° | 3 | 24° |
| October | 17° | 24° | 6 | 22° |
| November | 14° | 19° | 8 | 20° |
| December | 11° | 15° | 12 | 18° |
Kos in September and October
September may be the best month: 21–28°C, sea around 24°C and only about 3 rain days. October still works for the beach at 17–24°C with a sea of about 22°C, but rain days rise to about 6 and some hotels close late in the month.
Kos in May and June
May is good for walking and cycling (17–24°C), though the sea is still about 19°C. In June the sea reaches about 22°C before the August crowds, which suits families.
Kos in November and winter
November drops to 14–19°C with about 8 rain days; December and January are the wettest months. Resort areas such as Kardamena and Kefalos are largely closed, but Kos Town is open all year.
Wind on Kos
In summer the northerly meltemi often blows. It takes the edge off the heat but can make the sea rough on northern beaches; southern beaches around Kefalos are usually more sheltered.
When is the best time to visit Kos?
- Beaches: June to late September.
- Walking and cycling: May and October.
- Hottest: July–August, around 31°C.
More: Kos island guide, flights from Israel to Kos, Kos with kids and Greece weather by month.
FAQ
What is the weather like in Kos in October? On average 17–24°C, sea about 22°C and around 6 rain days. Swimming is still possible.
When is the sea warmest in Kos? In August and September, about 24–25°C on average.
Does it rain in Kos in summer? Rarely: about 3 rain days a month from June to September, usually short showers.
Is Kos open in winter? Kos Town is active all year, but most resort hotels close from November to April.
