Kefalonia weather by month: when to go
A monthly table of air and sea temperatures in Kefalonia, plus rainy days in spring and autumn, so you know when to go and what to pack.
- Summer is hot and dry: around 30°C in July and August, with the sea at about 25–26°C.
- September is excellent: still warm (about 27°C) and the sea is at its warmest.
- Rain starts in October (about 7 rainy days), and winter is cool and wet.
For a warm sea and fewer crowds, aim for late May–June or September. In winter, pack a light coat and umbrella and check which hotels and restaurants are open.
What is the weather like in Kefalonia through the year?
Kefalonia is the largest Ionian island, west of mainland Greece. It has a Mediterranean climate: hot, dry summers and milder but wetter winters than the Aegean islands. The averages below are from Greeka.
| Month | Air (min–max) | Sea | Rainy days |
|---|---|---|---|
| January | 9–14.5°C | 16°C | – |
| February | 9–15°C | 15°C | – |
| March | 10–16°C | 15°C | – |
| April | 12–19°C | 16°C | 5 |
| May | 15.5–23.5°C | 19°C | 3 |
| June | 19–27.5°C | 22.5°C | 1 |
| July | 21.5–30°C | 25°C | 1 |
| August | 22–31°C | 26.5°C | 1 |
| September | 20–27.5°C | 25.5°C | 4 |
| October | 17–24°C | 23°C | 7 |
| November | 13.5–20°C | 20°C | – |
| December | 10.5–16°C | 17.5°C | – |
The source does not publish rainy-day counts for winter, but November to March are clearly the wettest months.
Kefalonia weather in April and May
April evenings are still cool and the sea is cold for most swimmers (about 16°C). In May days reach about 23°C, the island is green and quiet, and the sea (about 19°C) is fine for a quick dip. It is a great time for villages and caves.
Kefalonia weather in July and August
The hottest and busiest months: 30–31°C, almost no rain, warm sea. Famous beaches such as Myrtos get crowded at midday. With children, go early in the morning or after 4pm.
Kefalonia weather in September and October
September is a favourite: the sea is at its warmest (about 25.5°C), the heat eases and crowds thin. Late September can bring the first rain. In October you can still swim (sea about 23°C), but expect about a week of rain, and some tourist businesses close towards the end of the month.
Kefalonia in winter
From November to March the island is very quiet: daytime 14–20°C, rain and wind, and many hotels and restaurants closed. It is a season for nature, walks and villages rather than beaches.
What to pack
- Summer: hat, sunscreen, water shoes for pebble beaches.
- Spring and autumn: a light jacket for evenings, and an umbrella in October.
- Winter: a coat, closed shoes and layers.
More on the island: Kefalonia guide, Kefalonia with kids and flights to Kefalonia from Israel. Greece's weather by month is on our weather page.
FAQ
When is the sea warmest in Kefalonia? In August and September, at about 25–26.5°C on average.
Can you swim in Kefalonia in October? Yes, the sea is still about 23°C on average, but there are around seven rainy days, so keep plans flexible.
What is Kefalonia like in May? Pleasant: about 15–23°C, little rain, and a refreshing sea of about 19°C.
When does it rain most in Kefalonia? From November to March. October already averages about a week of rain.
