The meltemi is the Aegean's personality. It is a dry, persistent, northerly wind that blows across the Greek islands from late June through September, reaching its peak intensity in July and August. The ancient Greeks called it the etesiai — the "annual winds" — and built their trading routes around it. The Venetians, who controlled the Aegean for centuries, timed their shipping schedules to its rhythm. The modern charter sailor who fails to understand the meltemi will have, at best, an uncomfortable week and, at worst, a dangerous one. The sailor who learns to read it will find some of the best sailing in the Mediterranean.
What the meltemi is and why it blows
The meltemi is a synoptic-scale wind driven by the pressure difference between a summer thermal low over Turkey and the eastern Mediterranean and a high-pressure system over the Balkans and central Europe. When this pressure gradient steepens — when the Turkish low deepens or the Balkan high strengthens — the meltemi accelerates.
It is not a thermal wind in the local sense (like Croatia's maestral, which builds with afternoon heating and dies at night). The meltemi can blow for days without pause, maintaining 20-30 knots through the night as well as the day. It is dry — it brings clear skies, excellent visibility, and no rain. It cools the islands, which without it would be stiflingly hot in midsummer.
The wind direction is predominantly north to northeast in the central Aegean (the Cyclades) and northwest in the eastern Aegean (the Dodecanese, the coast of Turkey). Local geography modifies this: islands funnel and accelerate the flow, headlands create wind shadows and acceleration zones, and the interaction of the meltemi with island topography produces complex local effects.
When it blows: the seasonal pattern
The meltemi season follows a roughly consistent annual pattern:
Late May to mid-June: Occasional meltemi events of 2-3 days, typically 15-20 knots. Manageable and intermittent.
Late June to mid-July: Frequency increases. The meltemi blows on most days, building to 20-25 knots by mid-morning and sustaining through the afternoon. Multi-day events of 4-5 days become common.
Mid-July to late August: Peak intensity. The meltemi at its strongest blows 25-35 knots, occasionally exceeding 40 knots in the most exposed channels. Events of 5-7 consecutive days are not unusual. The wind may moderate overnight to 15-20 knots but rarely dies entirely.
September: The meltemi weakens and becomes intermittent. Events of 2-3 days at 15-22 knots, with calmer intervals between. By late September, the pattern breaks down.
October: Occasional meltemi-type events, but the dominant pattern shifts to variable autumn winds.
Where it accelerates: the danger zones
The meltemi's behaviour is profoundly shaped by topography. Open channels between islands act as funnels, accelerating the wind by 30-50% above the ambient speed. The most notorious acceleration zones in the Cyclades:
The channel between Mykonos and Tinos: A narrow gap that regularly produces 35-40 knot gusts when the ambient meltemi is 25 knots. The sea state here can be vicious — steep, short-period waves that make progress to windward extremely difficult.
Cape Sounion and the Attic coast: Where the meltemi first meets the Cycladic channel, it accelerates around the cape. Boats sailing south from Lavrion to Kea sometimes encounter 5-10 knots more wind than forecast.
The strait between Paros and Naxos: Funnelling between the two largest central Cycladic islands produces some of the strongest winds in the chain.
Eastern sides of islands: The meltemi wraps around island topography, creating turbulent eddies on the southern and eastern coasts. Anchorages on the leeward side of an island may be uncomfortable despite being nominally sheltered, as the wind curves around the island and enters from unexpected directions.
Sailing in the meltemi: practical advice
Plan southward and downwind. The meltemi blows north to south. A downwind run from Kea to Santorini is exhilarating; the return beat is brutal. Structure your itinerary to move south during strong meltemi events and return north when the wind moderates.
Reef early. The meltemi does not build gradually like a thermal wind. It can increase from 18 to 30 knots in an hour as the pressure gradient tightens. A second reef in the main and a partially furled genoa is a sensible precaution from mid-morning onward.
Arrive early. Harbours and anchorages on the leeward side of islands — the south-facing bays that offer shelter from the north wind — fill quickly on meltemi days. Aim to arrive by early afternoon.
Respect the sea state. The meltemi produces short, steep seas in the channels between islands, particularly where wind meets current. These waves are more uncomfortable than their height suggests. Crew who are fine in 2m Atlantic swell may struggle with 1.5m Aegean chop.
Use wind shadows. The southern and western coasts of islands provide wind shadows that can reduce the meltemi to 5-10 knots within a mile of shore. Experienced Cycladic sailors use these shadows for respite and for coastal passages that avoid the full-force channels.
When to avoid the Aegean
For charterers who want Cycladic scenery without meltemi intensity, two options:
Sail in May or late September / early October. The meltemi is absent or light, the water is warm (September especially), and the islands are emptier than in high summer. The trade-off: some facilities close early or open late, and the weather is less predictable.
Sail the Ionian instead. The western Greek islands are sheltered from the meltemi by the Peloponnese landmass. The Ionian has its own wind pattern — a gentle northwesterly that rarely exceeds 15 knots in summer. It lacks the Cyclades' drama but offers a comfortable and beautiful alternative.
The meltemi is not an obstacle to be overcome — it is the Aegean's defining feature. The islands were shaped by it, the culture was built around it, and the sailing is better for its presence. The charterer who plans with it rather than against it will find a week in the Cyclades to be among the most rewarding in the Mediterranean.
