The best time to visit the Greek islands
By the Agoroam team · Published 20 August 2026
Quick answer
- June and September are the best months: warm sea, 26 to 30C air, everything open, and prices 30 to 50 percent below August.
- August is the most expensive, most crowded, and windiest month. Avoid it if you have any choice.
- The sea is warmest in late August and September, not in June.
- Most island infrastructure closes from late October to late April.
- May and October are excellent value with sea at 19 to 23C, which some people swim in and some do not.
The short answer
Go in June or September. Air temperature is 26 to 30C, the sea is warm, every restaurant and ferry is running, the crowds are half of August, and accommodation costs 30 to 50 percent less.
September has one specific advantage over June: the sea is at its warmest, around 24 to 25C, because it has spent the whole summer heating up. June sea temperature is around 22 to 23C, which is pleasant but noticeably cooler.
June has the advantage of longer days and a lower chance of the first autumn weather systems.
Month by month
Air temperature, sea temperature, and what to expect:
- April: 18 to 21C air, 17C sea. Many islands still closed. Cheap, green, and beautiful for walking.
- May: 22 to 25C air, 19 to 20C sea. Most places open by mid-month. Excellent value.
- June: 26 to 29C air, 22 to 23C sea. Everything open, moderate crowds. One of the two best months.
- July: 30 to 34C air, 24C sea. Hot, busy, expensive. Meltemi begins.
- August: 30 to 35C air, 25C sea. Peak crowds, peak prices, peak wind. Greeks holiday now too.
- September: 26 to 30C air, 24 to 25C sea. Warmest sea of the year. The best month overall.
- October: 22 to 25C air, 22 to 23C sea. Very good value, some closures from mid-month.
- November to March: 12 to 18C air. Most islands closed. Crete, Rhodes, and Corfu stay partly open.
What closes and when
This is the practical constraint that catches people out. Most Cycladic islands operate a genuine season from roughly late April to late October. Outside it, hotels close, restaurants close, ferry frequency drops to two or three sailings a week, and some islands have effectively no visitor infrastructure at all.
The exceptions are the large islands with permanent populations: Crete, Rhodes, and Corfu all function year round, with a reduced but real offering in winter.
If you are travelling in April or October, check specifically that your accommodation and at least a few restaurants on your chosen island are open for your dates. Do not assume.
The August problem
August is when Greeks themselves take holidays, particularly around 15 August, which is a major public holiday. Domestic demand stacks on top of international demand, and the result is the most expensive and most crowded fortnight of the year.
It is also the peak of the meltemi wind, which means the highest chance of a cancelled ferry precisely when the ferries are fullest and rebooking is hardest.
If you can only travel in August, book everything, ferries, accommodation, and the restaurants you care about, months in advance, and choose islands with more capacity such as Crete, Naxos, or Rhodes over small ones.
Shoulder season by island type
Large islands, Crete, Rhodes, and Corfu, have the longest seasons and the most reliable shoulder-season opening. They are the safe choice for April, May, and October.
Medium Cycladic islands, Naxos, Paros, and Milos, open from late April or early May and close through late October. Shoulder season here is excellent: warm, cheap, and calm.
Small islands, Folegandros, Koufonisia, Amorgos, and Sifnos, have the shortest seasons, sometimes only June to September, and the thinnest shoulder-season infrastructure.
Weather that is not temperature
Wind matters more in the Cyclades than temperature. The meltemi can make a 30C day feel cool, make swimming unpleasant on north-facing beaches, and close boat trips. Islands with sheltered south-facing coves, like Naxos and Paros, cope with it better than exposed ones.
Rain is almost absent from June to September and returns in October. April and May have occasional systems.
Sun intensity is severe from May to September. The UV index regularly hits 9 or 10, and a group that treats a 26C September day as mild will burn.
Frequently asked
What is the best month to visit the Greek islands?
September, closely followed by June. September has the warmest sea of the year at 24 to 25C, air temperatures of 26 to 30C, everything open, half the crowds of August, and prices 30 to 50 percent lower. June is similar with slightly cooler water and longer days.
When is the sea warmest in Greece?
Late August and September, at around 24 to 25C, because the sea has spent the whole summer heating up. June sea temperature is around 22 to 23C, and in May it is 19 to 20C, which is swimmable but noticeably cold.
Should you avoid the Greek islands in August?
If you have any choice, yes. August is when Greeks holiday as well as international visitors, particularly around the 15 August public holiday, so it is the most crowded and expensive fortnight of the year. It is also the peak of the meltemi wind and ferry cancellations.
Are the Greek islands open in winter?
Mostly not. Most Cycladic islands run a season from late April to late October, after which hotels and restaurants close and ferries drop to two or three sailings a week. Crete, Rhodes, and Corfu have permanent populations and function year round with a reduced offering.
Is May a good time to visit Greece?
Yes, and it is very good value. Air temperature is 22 to 25C, the islands are green rather than parched, most places are open from mid-month, and prices are low. The sea at 19 to 20C is the one drawback, swimmable for some and not for others.
Plan it with your crew.
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