Climate - Cephalonia (Greece)

The climate of Cephalonia (or Kefalonia), a Greek island of the Ionian Sea, is Mediterranean, with mild, rainy winters and hot, sunny summers. At sea level, the monthly average temperature ranges from 11.5 °C (52.5 °F) in January to 26.5 °C (79.5 °F) in August.
Here are the average temperatures in the town of Argostoli.

Rainfall amounts to about 800 millimeters (31.5 in) per year, and is concentrated in the period from October to April, while in summer, it rains very rarely. Here is the average precipitation.

In the interior, there are hills and mountains, which culminate in Mount Ainos, 1,628 meters (5,341 feet) high. The mountain slopes are greener and covered with forests.



Winter, from December to mid-March, is mild but rainy, especially in December and January. However, there is also a fair amount of sunny days. The island is sheltered from cold spells, so much so that it almost never snows at sea level, although it can sometimes snow in the mountains of the interior. However, a cold wind from the north can sometimes blow, and in the winter months, the minimum temperature at sea level can drop to 0 °C (32 °F).

Spring, from mid-March to May, is mild; the rains become gradually rarer, and sunny days become more and more frequent. May is a good month, before the summer heat.

Summer, from June to mid-September, is hot and sunny: the maximum temperature often exceeds 30 °C (86 °F), and it can even reach 35 °C (95 °F), especially in July and August; at the worst, it can reach 40 °C (104 °F). Luckily, sea breezes blow, providing relief, at least when the heat is not excessive, and in any case, you can cool yourself in the sea. This part of Greece, overlooking the Ionian Sea, is outside the area where the annoying but cooling Meltemi blows; as a consequence, here, the sea is warmer (see below).

Autumn, from mid-September to November, is mild (and initially, quite warm as well) and rainy. In October, there can still be many sunny days.



The amount of sunshine in Kefalonia is great in late spring and summer, when clear skies prevail. In contrast, from November to mid-March, sunny days alternate with periods of bad weather. Here are the average sunshine hours per day.

The temperature of the sea in Kefalonia is high enough for swimming from July to September, while it is still a bit cool in June. Here are the average sea temperatures.

Best Time

The best time to travel to Kefalonia for a beach holiday is from June to mid-September.
If you want to go on excursions on the island, the month of May or the first half of October are preferable in order to avoid the heat, at least at low altitude, while the summer is fine for mountain climbing.

Back to the Ionian Islands.

Cephalonia - Weather by month

Based on the period 1991-2020

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In January, the coldest month of the year, the weather in Cephalonia is usually mild. The average temperature is of 11.7 °C (53 °F), with a minimum of 8.9 °C (48.1 °F) and a maximum of 14.5 °C (58 °F).
On the coldest nights of the month, the temperature usually drops to around 3.5 °C (38.5 °F). However, it dropped to 0 °C (32 °F) in January 2002.
On the warmest days of the month, the temperature usually reaches around 17.5 °C (64 °F). However, it reached 20.6 °C (69.1 °F) in January 2015.
Precipitation amounts to 105 mm (4.1 in), distributed over 9 days.
The day lasts on average 9 hours and 55 minutes.
There are on average 4 hours of sunshine per day. So, the sun shines 40% of the time.
The average humidity is 71%. Hence, the air is normally humid.
The average wind speed is 13 kph (8 mph).
The average sea temperature is of 16 °C (60.5 °F). Therefore, the sea is cold for swimming.

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In February, the weather in Cephalonia is usually mild. The average temperature is of 11.8 °C (53 °F), with a minimum of 8.9 °C (48 °F) and a maximum of 14.7 °C (58.4 °F).
On the coldest nights of the month, the temperature usually drops to around 3.5 °C (38.5 °F). However, it dropped to -2 °C (28.4 °F) in February 1997.
On the warmest days of the month, the temperature usually reaches around 18.5 °C (65 °F). However, it reached 23.4 °C (74.1 °F) in February 2016.
Precipitation amounts to 85 mm (3.3 in), distributed over 9 days.
The day lasts on average 10 hours and 50 minutes.
There are on average 5 hours of sunshine per day. So, the sun shines 46% of the time.
The average humidity is 71%. Hence, the air is normally humid.
The average wind speed is 13 kph (8 mph).
The average sea temperature is of 15 °C (59.5 °F). Therefore, the sea is cold for swimming.

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In March, the weather in Cephalonia is usually mild. The average temperature is of 13.3 °C (56 °F), with a minimum of 10.3 °C (50.5 °F) and a maximum of 16.3 °C (61.4 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 5.5 °C (42 °F). However, it dropped to 2 °C (35.6 °F) in March 2011.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 20.5 °C (69 °F). However, it reached 24 °C (75.2 °F) in March 2001.
Precipitation amounts to 55 mm (2.2 in), distributed over 8 days.
The day lasts on average 12 hours and 0 minutes.
There are on average 6 hours of sunshine per day. So, the sun shines 50% of the time.
The average humidity is 71%. Hence, the air is normally humid.
The average wind speed is 13 kph (8 mph).
The average sea temperature is of 15 °C (59.5 °F). Therefore, the sea is cold for swimming.

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In April, the weather in Cephalonia is usually very mild. The average temperature is of 15.7 °C (60 °F), with a minimum of 12.3 °C (54.1 °F) and a maximum of 19.1 °C (66.3 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 8 °C (46 °F). However, it dropped to 4 °C (39.2 °F) in April 2003.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 24.5 °C (76 °F). However, it reached 32 °C (89.6 °F) in April 2018.
Precipitation amounts to 50 mm (2 in), distributed over 5 days.
The day lasts on average 13 hours and 10 minutes.
There are on average 8 hours of sunshine per day. So, the sun shines 61% of the time.
The average humidity is 71%. Hence, the air is normally humid.
The average wind speed is 12 kph (7 mph).
The average sea temperature is of 16 °C (61 °F). Therefore, the sea is cold for swimming.

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In May, the weather in Cephalonia is usually warm. The average temperature is of 19.5 °C (67 °F), with a minimum of 15.6 °C (60.2 °F) and a maximum of 23.4 °C (74 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 11 °C (52 °F). However, it dropped to 9 °C (48.2 °F) in May 1998.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 29 °C (84.5 °F). However, it reached 36 °C (96.8 °F) in May 2020.
Precipitation amounts to 20 mm (0.8 in), distributed over 3 days.
The day lasts on average 14 hours and 20 minutes. So the days are long.
There are on average 10 hours of sunshine per day. So, the sun shines 70% of the time.
The average humidity is 70%.
The average wind speed is 11 kph (7 mph).
The average sea temperature is of 19 °C (66 °F). Therefore, the sea is very cool for swimming.

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In June, the weather in Cephalonia is usually warm to hot. The average temperature is of 23.4 °C (74 °F), with a minimum of 19.3 °C (66.8 °F) and a maximum of 27.5 °C (81.6 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 15 °C (59 °F). However, it dropped to 13 °C (55.4 °F) in June 2012.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 33.5 °C (92 °F). However, it reached 36 °C (96.8 °F) in June 2012.
Precipitation amounts to only 5 mm (0.2 in), and all occurs in one day.
The day lasts on average 14 hours and 50 minutes. So the days are long. June 21, the summer solstice, is the longest day of the year in the Northern Hemisphere.
There are on average 11 hours of sunshine per day. So, the sun shines 74% of the time.
The average humidity is 67%.
The average wind speed is 11 kph (7 mph).
The average sea temperature is of 22.5 °C (72.5 °F). Therefore, the sea can be considered barely acceptable for swimming.

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In July, the weather in Cephalonia is usually warm to hot. The average temperature is of 26 °C (79 °F), with a minimum of 21.7 °C (71 °F) and a maximum of 30.3 °C (86.6 °F).
On the coldest nights of the month, the temperature usually drops to around 18 °C (64.5 °F). However, it dropped to 15.8 °C (60.4 °F) in July 2017.
On the warmest days of the month, the temperature usually reaches around 35 °C (95 °F). However, it reached 40 °C (104 °F) in July 2000.
Precipitation amounts to 10 mm (0.4 in), and all occurs in one day.
The day lasts on average 14 hours and 30 minutes. So the days are long.
There are on average 12 hours of sunshine per day. So, the sun shines 83% of the time.
The average humidity is 64%.
The average wind speed is 12 kph (8 mph).
The average sea temperature is of 25 °C (77 °F). Therefore, the sea is warm enough for swimming.

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In August, the hottest month of the year, the weather in Cephalonia is usually warm to hot. The average temperature is of 26.6 °C (80 °F), with a minimum of 22.3 °C (72.2 °F) and a maximum of 30.9 °C (87.6 °F).
On the coldest nights of the month, the temperature usually drops to around 19 °C (66 °F). However, it dropped to 17 °C (62.6 °F) in August 2001.
On the warmest days of the month, the temperature usually reaches around 35.5 °C (95.5 °F). However, it reached 39 °C (102.2 °F) in August 2007.
Precipitation amounts to 10 mm (0.4 in), and all occurs in one day.
The day lasts on average 13 hours and 35 minutes.
There are on average 12 hours of sunshine per day. So, the sun shines 88% of the time.
The average humidity is 64%.
The average wind speed is 12 kph (7 mph).
The average sea temperature is of 26.5 °C (79.5 °F). Therefore, the sea is pleasantly warm and allows long swims.

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In September, the weather in Cephalonia is usually warm to hot. The average temperature is of 23.6 °C (75 °F), with a minimum of 19.8 °C (67.7 °F) and a maximum of 27.4 °C (81.4 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around 16 °C (60.5 °F). However, it dropped to 11 °C (51.8 °F) in September 2015.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 31.5 °C (88.5 °F). However, it reached 34 °C (93.2 °F) in September 2020.
Precipitation amounts to 55 mm (2.2 in), distributed over 4 days.
The day lasts on average 12 hours and 25 minutes.
There are on average 10 hours of sunshine per day. So, the sun shines 81% of the time.
The average humidity is 69%.
The average wind speed is 11 kph (7 mph).
The average sea temperature is of 25.5 °C (77.5 °F). Therefore, the sea is warm enough for swimming.

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In October, the weather in Cephalonia is usually warm. The average temperature is of 20.3 °C (69 °F), with a minimum of 16.9 °C (62.4 °F) and a maximum of 23.7 °C (74.6 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around 12.5 °C (54.5 °F). However, it dropped to 9 °C (48.2 °F) in October 2011.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 28 °C (82.5 °F). However, it reached 33 °C (91.4 °F) in October 1991.
Precipitation amounts to 80 mm (3.1 in), distributed over 7 days.
The day lasts on average 11 hours and 10 minutes.
There are on average 7 hours of sunshine per day. So, the sun shines 63% of the time.
The average humidity is 72%. Hence, the air is normally humid.
The average wind speed is 11 kph (7 mph).
The average sea temperature is of 23 °C (73.5 °F). Therefore, the sea can be considered barely acceptable for swimming.

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In November, the weather in Cephalonia is usually very mild. The average temperature is of 16.7 °C (62 °F), with a minimum of 13.7 °C (56.7 °F) and a maximum of 19.7 °C (67.4 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around 9 °C (48 °F). However, it dropped to 5 °C (41 °F) in November 2006.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 24 °C (75.5 °F). However, it reached 29 °C (84.2 °F) in November 2002.
Precipitation amounts to 140 mm (5.5 in), distributed over 11 days.
The day lasts on average 10 hours and 5 minutes.
There are on average 5 hours of sunshine per day. So, the sun shines 50% of the time.
The average humidity is 74%. Hence, the air is normally humid.
The average wind speed is 12 kph (8 mph).
The average sea temperature is of 20 °C (68 °F). Therefore, the sea is very cool for swimming.

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In December, the weather in Cephalonia is usually mild. The average temperature is of 13.2 °C (56 °F), with a minimum of 10.4 °C (50.8 °F) and a maximum of 16 °C (60.8 °F).
On the coldest nights of the month, the temperature usually drops to around 5 °C (41 °F). However, it dropped to -1 °C (30.2 °F) in December 1992.
On the warmest days of the month, the temperature usually reaches around 20 °C (68 °F). However, it reached 22 °C (71.6 °F) in December 2010.
Precipitation amounts to 190 mm (7.5 in), distributed over 13 days.
The day lasts on average 9 hours and 35 minutes. December 21, the winter solstice, is the shortest day of the year in the Northern Hemisphere.
There are on average 4 hours of sunshine per day. So, the sun shines 42% of the time.
The average humidity is 73%. Hence, the air is normally humid.
The average wind speed is 13 kph (8 mph).
The average sea temperature is of 17.5 °C (63.5 °F). Therefore, the sea is cold for swimming.