Kos weather in May
May in Kos: warm, dry, with muggy air — an excellent time to visit.
Updated September 2026 · climate normals from ERA5 reanalysis
#6 of 12 months in Kos · #591 of 1413 destinations to visit in May · comfort 83/100 (tier A)
- Days
- 24°C
- Nights
- 18°C
- Wet days
- 3
- Sun
- 12.5 h
- Humidity
- 77%
- Daylight
- 14 h

Traveller notes on Kos in May
Notes from nearby Rhodes (98 km away)
Kos doesn't have its own notes for May yet — these are about Rhodes, close enough to share the season.
Regulars are consistent that weather here has more or less settled by mid-month, temperatures climbing past 30C by the end, with cloud or a little rain now the genuine exception rather than something to plan around. Our row backs that warm, genuinely dry read, 24.2C over 18.1C nights, with rain minimal at 13.4mm across just 3.1 days and humidity at 76 percent. Regulars are specific that the island's southeast side runs slightly warmer and drier than elsewhere, a real factor worth weighing when picking a base. The sea sits at a cool 19.6C, not yet warm enough for most to swim comfortably despite the reliably sunny days on land. The record: 12.5 hours of sun, a 21.8 kph wind and AQI 61.
Other months in Kos
Forum posters describe March in Kos as genuinely unpredictable but still mild overall, sitting outside the reliably hot, dry stretch that runs roughly June through early October. Posters note showers this time of year can affect one side of the island while leaving another completely dry, reflecting how localized spring weather patterns can be here. Posters consistently recommend packing layers and a light raincoat for a March visit, ready for both sunny stretches and passing rain within the same trip. Posters generally rate March as a mild, changeable shoulder-season month for Kos, well ahead of the settled summer heat but past the harshest of the Aegean winter.
September is the month Kos regulars call the best of the year — 25 to 30°C, the sea still at 27°C, everything open, and nowhere near July and August's crowds. Evenings want a cardigan. The thing to understand about the wind is that it is directional rather than seasonal: the meltemi is a northerly running June to about mid-September, so it hits the north coast hardest — Tigaki and Mastihari especially — and the forum's fix is simply to switch sides of the island, Kardamena being the usual suggestion. Kos reads breezy year-round on the monthly averages, but an average smooths over exactly the local, directional effect regulars are describing, so take the coast advice over the number. In the heat most people count it a cooling breeze rather than a problem.
Add your own note from Kos's card on the map.
Kos climate normals — May
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Crowds in Kos in May
How busy the place itself is — school and mass holidays, the months an editor tagged, and how sought-after the weather makes them. Never part of the comfort score.
BusyCharter and resort season, school holidays in 4 of the markets that fill it(estimated)
Peak crowdsBusyShoulder seasonQuiet
Best months for Kos's weather
Ranked by this destination's own climate comfort score across the year — a different thing from how busy it gets (see Crowds above).
Fair weatherKos's best weather comes in June, August and September — separate windows, not one continuous season.
Best weatherFair weatherToughest weather
What's on in Kos in May
Recurring seasonal events, natural spectacles, closures and holidays — curated and sourced.
- Season
Charter and resort season
1 May – 15 Oct · usuallySummer season opensCrowdedKardamena, Tigaki and Mastichari run on northern European charter flights, and the hotels, bike hire and beach bars open and close with them. Outside the season the airport goes back to a couple of Athens flights a day.
Nearby, and something's on
Within 300 km of Kos — a day trip or a short hop — with something on this month. Never part of the comfort score.
Where is Kos?
Kos in May — FAQ
- Is May a good time to visit Kos?
- May in Kos: warm, dry, with muggy air — an excellent time to visit. It ranks #6 of 12 months for Kos on SeasonMap's comfort score (83/100).
- What is the weather like in Kos in May?
- In May, Kos averages a daily high of 24°C and a low of 18°C, with about 10.9 mm of rain over roughly 2.8 rainy days.
- What is the air quality in Kos in May?
- Kos has a mean US Air Quality Index of about 58 in May.
Within 300 km: Rhodes' Resort season opens around 1 Apr – 10 May, and Selçuk's Storks on the aqueduct around 15 Mar – 31 Aug.