Sea conditions
Meltemi alerts & ferry outlook
Live wind across Greek waters and what it means for your boat. Fast catamarans stop first; big ferries keep going.
Seasonal warning
Outside Meltemi season. Autumn and winter storms are less frequent but stronger — sailing bans can last 1–2 days.
Live wind by sea area
Attica
Piraeus / Saronic
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Cyclades (north)
Rafina / Andros strait
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Cyclades (central)
Mykonos & Tinos
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Cyclades (central)
Paros & Naxos
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Cyclades (west)
Milos & Folegandros
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Cyclades (south)
Santorini & Ios
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Crete
Heraklion (Sea of Crete)
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Dodecanese
Rhodes & Kos
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North Aegean
Lesvos & Chios
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Sporades
Skiathos & Skopelos
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Ionian
Corfu strait
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Ionian
Kefalonia & Zakynthos
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Ferry outlook is an estimate based on live wind (Open-Meteo). Only the Hellenic Coast Guard and the ferry operator can confirm a cancellation — check your operator's site, call the port authority, or ask at the ticket office.
Beaufort scale for ferry travellers
| Bf | Name | Wind | What it means at sea |
|---|---|---|---|
| 0 | Calm | 0–1 km/h | Glassy sea. All boats run. |
| 1 | Light air | 2–5 km/h | Ripples. All boats run. |
| 2 | Light breeze | 6–11 km/h | Small wavelets. All boats run. |
| 3 | Gentle breeze | 12–19 km/h | Crests begin to break. Comfortable on all vessels. |
| 4 | Moderate breeze | 20–28 km/h | Small waves. Catamarans start to feel bumpy. |
| 5 | Fresh breeze | 29–38 km/h | Moderate waves. Fast boats bouncy; seasickness likely. |
| 6 | Strong breeze | 39–49 km/h | Large waves. Small high-speed craft may be held; delays likely. |
| 7 | Near gale | 50–61 km/h | Coast Guard often bans catamarans/Flying Dolphins. Big conventional ferries usually still sail. |
| 8 | Gale | 62–74 km/h | Port authorities may ban all departures from affected ports. |
| 9 | Strong gale | 75–88 km/h | General sailing ban (apagorefsi) very likely. |
| 10+ | Storm+ | 89+ km/h | All sailings cancelled. |
Meltemi survival guide
- The Meltemi is a dry north wind that blows across the Aegean from mid-May to mid-September, peaking in July and August.
- It typically builds late morning, peaks in the afternoon (often Beaufort 6–7, gusts 8) and eases at night — morning boats are more reliable.
- Episodes last 3–7 days. The central and eastern Cyclades (Mykonos, Tinos, Andros, Naxos, Paros, Amorgos) are hit hardest; the Ionian is barely affected.
- Catamarans and high-speed craft (SeaJets, Flying Cat, WorldChampion Jet) are restricted first — usually from Beaufort 7 under Coast Guard rules.
- Large conventional ferries (Blue Star, Hellenic Seaways, Minoan, ANEK) keep sailing until Beaufort 8–9, though they may leave late.
- Never book an island ferry for the day of an international flight in July–August. Keep a buffer day in Athens.
- If your fast boat is cancelled, the operator must offer a refund or rebooking; ask about a seat on the conventional ferry the same day.
Heading to port? See the port navigation guides for Piraeus, Rafina and Heraklion.