Mykonos Greece Weather, Month by Month
Mykonos is called the island of the winds and it is not a nickname. The temperature here is easy; the wind is the variable that changes what you can do on a given day, and it is the one nobody plans for. A morning Mykonos catamaran tour is the calmer booking in July and August, because the wind builds through the day.
What the meltemi does to a day here
The meltemi is a dry north wind that blows across the Aegean from June to September. It is strongest in July and August, typically force five to seven on the Beaufort scale, gusting eight, and it is stronger by day than by night. It is why the island is bare, why the windmills were built, and why the boats here carry a clause about the captain's discretion.
What it does not do is cancel your day. Three of the operators in this list write into their own listings that the route may change when the wind is up, usually to the sheltered south coast of Mykonos, and travellers who were told in advance rated those days five stars anyway. The fix is simple: put the boat on the calmest morning you have, keep the land plans for the windy afternoon, and book something that refunds at 24 hours.
Book the morning, not the afternoon
The wind eases overnight and builds through the day, so an early sailing is the calmer one in July and August.
Mykonos month by month
January
12.6 °C by day, 9.2 °C at night, and 100 mm of rain over about ten days. The sea is 16 °C. Delos is closed and the Delos boats are not running. Most of the tours in this list do not sail, and the Chora is a working Greek town rather than a resort.
February
13 °C by day and 70 mm of rain across eight days, with five hours of sun. The sea drops to its annual low of 15.5 °C. Delos stays shut. If you come now, come for the town and the light, not for the water.
March
15 °C by day, 60 mm of rain, six and a half hours of sun. The sea is still 15.5 °C. Delos reopens on 1 April, so a March visit misses it by days. Ferry frequency starts to build in the second half of the month.
April
18 °C by day and rain drops to 25 mm across five days. The Delos site opens on the 1st, the licensed boats start their season the same day, and the Sea Bus between the ports begins running. The sea is 16 °C, which is swimmable and bracing. The first cruises of the year sail.
May
22.3 °C by day, 15 mm of rain over three days, nine and a half hours of sun and an 18.5 °C sea. The meltemi has not settled in yet, so this is among the calmest months on the water. Everything is open and nothing is full. The strongest month for a boat day if you dislike wind.
June
26.7 °C by day, effectively no rain, eleven hours of sun and a 21.5 °C sea. The meltemi starts, usually as an afternoon wind rather than an all-day one. Book morning sailings from here on. Prices and crowds both climb through the month.
July
28.5 °C by day, 22.9 °C at night, twelve hours of sun and 2 mm of rain. The sea reaches 23.5 °C. The meltemi is at its strongest, force five to seven with gusts to eight, and it is the month operators most often re-route to the south coast. Everything is booked ahead.
August
28.4 °C by day and 23.2 °C at night — the warmest nights of the year — with a 24 °C sea and eleven and a half hours of sun. The wind is as strong as July's. This is the busiest and most expensive month, and the one where booking a boat three to five days ahead stops being optional.
September
25.7 °C by day, 10 mm of rain, nine and a half hours of sun, and the sea still at 23.5 °C. The meltemi eases through the month. Everything is open, the cruise calendar is still full and the prices start to come off. For most travellers this is the month to pick.
October
21.9 °C by day and 45 mm of rain over five days, with a 21.5 °C sea. The Sea Bus stops on the 31st and the last afternoon Delos sailing runs on the 26th. Boat operators start thinning their timetables. A good month, with a firm end date attached to it.
November
17.8 °C by day, 65 mm of rain over six days, five and a half hours of sun. Delos closes on 30 November and its hours shorten to 08:00–16:00 for the whole month. Most cruises have stopped. The island empties and the tavernas that stay open are the local ones.
December
14 °C by day and 100 mm of rain across ten days, the wettest month with January. The sea holds 17 °C, warmer than it will be in March. Delos is shut from the 1st. Come for a quiet Cycladic town, not for a boat.
The sea, and when it is warm enough
| Month | Max °C | Min °C | Rain mm | Rain days | Sun hrs/day | Sea °C |
|---|---|---|---|---|---|---|
| January | 12.6 | 9.2 | 100 | 10 | 3.5 | 16 |
| February | 13.0 | 9.5 | 70 | 8 | 5.0 | 15.5 |
| March | 15.0 | 11.1 | 60 | 7 | 6.5 | 15.5 |
| April | 18.0 | 13.2 | 25 | 5 | 8.5 | 16 |
| May | 22.3 | 16.7 | 15 | 3 | 9.5 | 18.5 |
| June | 26.7 | 20.8 | 4 | 1 | 11.0 | 21.5 |
| July | 28.5 | 22.9 | 2 | 0 | 12.0 | 23.5 |
| August | 28.4 | 23.2 | 2 | 0 | 11.5 | 24 |
| September | 25.7 | 20.7 | 10 | 2 | 9.5 | 23.5 |
| October | 21.9 | 17.6 | 45 | 5 | 7.5 | 21.5 |
| November | 17.8 | 14.2 | 65 | 6 | 5.5 | 19 |
| December | 14.0 | 10.7 | 100 | 10 | 3.5 | 17 |
The sea lags the air by about two months, which is the number most people get wrong. August is the warmest water of the year at 24 °C, not July. October still holds 21.5 °C, warmer than June. And February, not January, is the coldest at 15.5 °C. If swimming is the point of the trip, the window is genuinely June to October rather than July and August.
Wind, and what it means for a boat booking
Three practical consequences, each with something you can do about it. The route may move — south coast instead of Rhenia — so pick a cruise whose swim stop you would enjoy either way. The operator may cancel if conditions are bad, in which case you are offered another date or a full refund, which is written into these listings rather than left to goodwill. Boarding may be wetter than you expect: several of these boats load by tender from a beach jetty, so dry bags and sensible shoes earn their place.
Which months those apply to, and which trips run all season, is set out on the best time to visit.
What to wear and what to bring
June to September: Light layers, and one windproof layer that packs small. The evening wind off the water is cooler than the day suggests
Sun: Twelve hours of it a day in July. The sea breeze hides how strong it is, and the boats have limited shade
Feet: Cobbles and steps in the Chora, uneven ancient stone on Delos. Sandals with a sole rather than flip-flops
Towels: Two of these cruises exclude them in writing and one asks you to bring your own. Pack one for any boat day
April, May, October and November: Add a proper jacket. The rain comes back in October and the wind is colder without the summer sun behind it
Questions about Mykonos weather
What happens if the meltemi is blowing?
Will a boat trip be cancelled in wind?
Can I swim on every boat trip?
Is there shade on the boats?
What should I bring on a boat day?
Mykonos Greece Tours lists which trips run through the shoulder months and which stop.
Sources
Checked on 5 September 2026. Climate figures are long-term station averages, not a forecast. The seasonal dates for Delos and the Sea Bus are the operators' and the ministry's own.
Pick a calm morning
Every boat day here refunds in full up to 24 hours before it sails, so a forecast that turns is not a fare you lose.
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