Best months to visit
AprilMayOctober
May, June and September are best for combining beach with sightseeing. October is excellent for off-season visits — sea is still warm at 22-23 °C and crowds are much lighter. November is genuinely usable for swim-and-walk if you accept that some beach services have closed.
Best for
Beach
Mid-May to October — sea 21-26 °C, warmest in August. Long sandy beaches at Tigaki, Marmari and Mastichari run full season.
Hiking
April to early June and October to early November — Mt. Dikeos and inland villages comfortable at 18-25 °C; midsummer is too hot.
Sightseeing
April to June and September to October — Asclepeion, Hippocrates plane tree, Kos Town all comfortable at 22-28 °C.
Climate notes
- Hot dry summer (June-September): less than 10 mm rain per month, highs of 28-31 °C, meltemi cooling on the north coast.
- Long swimming season: sea temperature stays above 20 °C from June through December — the longest in the central Aegean thanks to warm Asia Minor coastal waters.
- Meltemi wind: peaks July-August at 30-50 km/h, creating excellent windsurfing conditions at Mastichari and Marmari on the north coast.
- Mild long winter: 13-15 °C daytime in January-February, sea still 17-18 °C — Kos is among the mildest winter destinations in the Aegean.
- Higher autumn rainfall than the Cyclades: about 150 mm in November-December alone, thanks to the proximity of mainland Asia Minor weather systems.
- Fire risk (July-September): moderate to high in the Dikeos massif and the eastern olive groves; the island has had recent significant fires.
Temperature (min / max °C)
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Regional notes
- Kos Town and the east: the busiest tourist hub, average winds, sandy bays.
- Mastichari and Marmari (north coast): catch the meltemi; the windsurfing centres of Kos.
- Kefalos peninsula (southwest): more sheltered from the meltemi, slightly warmer summer afternoons.
- Mt. Dikeos (846 m): cooler, slightly wetter, the inland villages of Asfendiou and Zia stay 3-5 °C cooler than the coast on hot days.
Frequently asked questions
When is the best time to visit Kos?
May, June, September and October offer warm sea (21-26 °C), comfortable air, and lighter crowds than the July-August peak when northern European package tourism dominates.
Can you swim in Kos in November?
Yes — sea temperature in November averages 21-22 °C, dropping to 19 °C in December. November is comfortable for swimming, December borderline. Most beach services close in mid-October.
How hot does Kos get in summer?
Daytime highs average 30-32 °C in July and August. Inland Asfendiou and Zia stay 3-5 °C cooler. Heatwaves can push coastal temperatures to 36-38 °C briefly.
Is Kos good for windsurfing?
Yes — Mastichari and Marmari on the north coast are well-known windsurfing centres, with reliable meltemi winds 25-35 knots most July-August afternoons.
Is Kos rainier than the Cyclades?
Yes, somewhat — about 540 mm annual versus 280-330 mm in central Cyclades. November-December are notably wetter, thanks to Asia Minor weather systems. Summer is similarly dry.
Are there many fires on Kos?
Some — the island has had several significant wildfire events in recent years, especially in the Dikeos massif and pine forests. Coastal resorts are rarely affected directly. Check 112 alerts before hiking.
What is the weather like in winter?
Mild but with intense storm events. December-February averages 14-16 °C daytime, 9-11 °C nights, with about 130-150 mm of rain per month. Many beach hotels close, but Kos Town has a year-round community.
Does it ever snow on Kos?
Practically never on the coast. Mt. Dikeos (846 m) gets occasional dustings in January-February, but it rarely settles for long.
Climate data: Open-Meteo · 2020–2025