The Ionian Islands are located in the western part of Greece, and have a Mediterranean climate, with mild and rainy winters, and hot and sunny summers.

The seven main islands (the old Heptanese) are:
- Corfu, the northernmost of the main islands and the second largest, with its 592 square kilometres (228 square miles).
- Paxos.
- Lefkada; it has an area of 336 square km (130 sq mi).
- Ithaca, 118 square km (45 sq mi).
- Kefalonia, the largest, with its 781 square km (301 sq mi).
- Zakynthos (or Zante), the southernmost of the actual Ionian Islands. It has an area of 408 square km (157 sq mi).
- Cythera (or Cerigo), is located south of Attica, in a position isolated from the other islands, so it has also a slightly different climate, less rainy in the cold half of the year, and a little less hot in summer.
There are also some small islands:
- the Diapontian Islands, the northernmost ones, located northwest of Corfu: Erikoussa (or Merlera), Mathraki, Othoni (or Fanò).
- Kalamos, Kastos and Meganisi, between Lefkada and the mainland.
- Other islands such as Antipaxos, Arkoudi, Atokos, Oxeia.

Being outside of the area where the Meltemi blows, in these islands in summer it can get very hot: temperatures can reach 35/36 °C (95/97 °F), but sometimes even 40 °C (104 °F). In winter, sometimes there are periods of a few days with a cold wind from the north, although a very cold weather is rare: in practice, in the plains it does not snow and it never freezes, while snowfalls may occur in the interior of the islands that are home to hills or mountains.
Here, for example, the average temperatures of Paxos.
Average temperatures - Paxos

Paxos	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Paxos	J	F	M	A	M	J	J	A	S	O	N	D
Min (°C)	5	6	7	9	13	16	18	19	16	13	10	7
Max (°C)	14	14	16	19	24	28	31	31	28	23	19	15
Min (°F)	41	43	45	48	55	61	64	66	61	55	50	45
Max (°F)	57	57	61	66	75	82	88	88	82	73	66	59

The rains in the Ionian Islands are quite abundant, since they generally exceed 800 millimetres (31.5 inches) per year, but above all they can be abundant from October to March, because the islands are exposed to both the south and west winds. In summer, it rains very rarely, as normally occurs in the regions having a Mediterranean climate.
Here for example, the average rainfall in Argostoli, in the island of Kefalonia.
Average precipitation - Cephalonia

Cephalonia	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Year
Cephalonia	J	F	M	A	M	J	J	A	S	O	N	D	Y
Prec. (mm)	100	95	75	60	20	10	5	10	40	95	105	110	725
Prec. (in)	3.9	3.7	3	2.4	0.8	0.4	0.2	0.4	1.6	3.7	4.1	4.3	28.5
Days	13	13	10	10	5	2	1	2	4	10	13	14	97

The amount of sunshine in the Ionian Islands is excellent in late spring and in summer, when clear skies prevail. From November to mid-March, on the contrary, sunny days alternate with periods of bad weather.
Here are the average daily sunshine hours in Lefkada.
Sunshine - Lefkada

Lefkada	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Lefkada	J	F	M	A	M	J	J	A	S	O	N	D
Sun (hours)	5	5	6	8	9	11	13	12	9	7	5	4

The temperature of the sea in the Ionian Islands is high enough for swimming from July to September, while in June it is still a little cool, around 22 °C (72 °F), but it's overall acceptable. Here, for example, the temperature of the sea in Lefkada.
Sea temperature - Lefkada

Lefkada	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Lefkada	J	F	M	A	M	J	J	A	S	O	N	D
Sea (°C)	16	15	15	16	18	22	24	26	25	22	19	17
Sea (°F)	61	59	59	61	64	72	75	79	77	72	66	63

The best time to go to the Ionian islands, for swimming and sunbathing, goes from June to August, or even mid-September, especially in the southernmost islands (Cephalonia, Zakynthos, Kythira), where summer lasts a little longer.

Back to the Greek Islands.