Weather and the Impact of Synoptic Systems on Sailing Areas in Greece
The data in this document is based on meteorological information from global models such as ECMWF and GFS, as well as marine forecasts from services like PredictWind and Windy, and historical data from the National Hellenic Meteorological Service. Additionally, the information is based on typical weather patterns observed over the years in Greece, taking into account the influence of synoptic systems on various sailing regions.
For sailing in Greece, it is recommended to use reliable forecasting sources that provide real-time data on wind, waves, and precipitation. Below are some leading services:
- Windy (windy.com) – Presents wind and sea forecasts based on global models (ECMWF, GFS), with interactive maps.
- PredictWind (predictwind.com) – Designed specifically for sailors, includes wind, wave, and current data.
- Poseidon System (poseidon.hcmr.gr) – A marine meteorological service dedicated to Greece, offering highly accurate local forecasts.
- Meteo Greece (meteo.gr) – Provides regional forecasts, including severe weather warnings.
- NOAA (weather.gov) – Global-scale atmospheric forecasts, with an emphasis on large synoptic systems.
Using multiple sources in parallel helps ensure a more reliable overview for planning your sailing trip.
You can see under “Useful Apps” recommended weather applications
Overview of Weather Systems in Greece by Season
Spring (April–May)
This season is characterized by a gradual transition from winter to summer weather.
Main synoptic systems:
- Upper-level troughs from the west may bring light rain, especially in northern Greece and the Ionian Sea.
- Variable wind directions, generally moderate (5–15 knots).
- Relatively calm seas, though unstable conditions may occasionally arise.
Summer (June–August)
The driest season in Greece, dominated by stable upper-level systems.
Main synoptic systems:
- A barometric ridge from the west leads to dry conditions and minimal rainfall.
- Meltemi winds – Strong winds from the north to northeast, especially in the Aegean Sea.
- Wind speeds of 20–30 knots, sometimes higher.
- Wave height of 2–3.5 meters, particularly around the Cyclades and Dodecanese.
- In the Ionian Sea and Saronic Gulf, winds are lighter and sailing conditions are more comfortable.
Autumn (September–October)
Autumn begins with stable weather and good sailing conditions, but becomes stormier toward the end.
Main synoptic systems:
- Gradual weakening of the Meltemi.
- Upper-level troughs from the Adriatic and Italy may bring rain and strong southern winds.
- Mediterranean Hurricanes (Medicanes) – Local storms with winds over 35 knots and rough seas, mainly in the Ionian Sea.
Impact of Synoptic Systems on Major Sailing Regions in Greece
Corfu and the Ionian Sea
- Spring: Moderate winds (5–15 knots), mainly southwesterly. Generally stable weather with occasional light rain in the north. Calm seas.
- Summer: Northwesterly winds (10–20 knots). Less affected by the Meltemi, making for easier sailing. Waves of 0.5–2 meters.
- Autumn: Good conditions at the beginning of the season, but by late October Medicanes may bring strong winds and rough seas.
The Cyclades (Mykonos, Paros, Milos, Syros, etc.)
- Spring: Variable winds, mainly northwesterly (10–15 knots). Generally calm seas, but occasional rough days.
- Summer: Heavily affected by the Meltemi – strong winds (25–35 knots or more). Waves of 3–4 meters, making sailing challenging.
- Autumn: The Meltemi weakens and conditions become more manageable. Occasionally, southern troughs bring rain and strong southerly winds.
The Sporades (Skiathos, Skopelos, Alonissos, etc.)
- Spring: Light to moderate winds (5–15 knots), relatively calm seas, with possible localized showers.
- Summer: Affected by the Meltemi but to a lesser extent than the Cyclades (15–25 knots). Waves of 1.5–2.5 meters – generally a comfortable sailing area.
- Autumn: Winds ease. Occasionally, strong southerly winds and local troughs may appear.
Thessaloniki and the Northern Aegean
- Spring: Good sailing conditions, moderate winds (5–15 knots), low waves, minimal rain.
- Summer: Affected by the Meltemi, but less intensely than the Cyclades (15–25 knots). Wave height of 1.5–2 meters.
- Autumn: Stable early season, but strong southern winds and rainy systems may occur in late October.
Lefkada and the Southern Ionian Sea
- Spring: Light to moderate winds (5–12 knots), calm seas (0.5–1.5 meters).
- Summer: Northwesterly winds (10–20 knots). No Meltemi effect – a comfortable sailing zone. Waves of 1–2 meters.
- Autumn: The beginning of the season is favorable, but by late October, troughs from the Adriatic may bring rain and local storms.
The Saronic Islands (Athens, Hydra, Poros, Aegina, Spetses)
- Spring: Good sailing conditions, moderate winds (5–15 knots), minimal rainfall.
- Summer: A relatively protected area from the Meltemi – moderate winds (10–20 knots). Generally calm seas with low waves (1–2 meters).
- Autumn: Early autumn is pleasant, but strong southerly winds and frontal systems with rain may occur later in the season.
Summary and Seasonal Recommendations for Sailing in Greece
- Best time to sail: Spring (April–May) and Autumn (September–October), when winds are more moderate.
- Most challenging time: Summer (June–August), especially in the Cyclades due to the Meltemi.
- Easiest summer sailing zones: The Ionian Sea and the Saronic Islands, where the Meltemi has less impact.
- Caution in late autumn: Troughs and Medicanes in the Ionian Sea may create difficult conditions.
Wind Barbs
Beaufort Wind Scale
Developed in 1805 by Sir Francis Beaufort, U.K. Royal Navy
| Force | Wind (Knots) | WMO Classification | Appearance of Wind Effects | ||
|---|---|---|---|---|---|
| On the Water | On Land | ||||
| 0 | Less than 1 | Calm | Sea surface smooth and mirror-like | Calm, smoke rises vertically | |
| 1 | 1-3 | Light Air | Scaly ripples, no foam crests | Smoke drift indicates wind direction, still wind vanes | |
| 2 | 4-6 | Light Breeze | Small wavelets, crests glassy, no breaking | Wind felt on face, leaves rustle, vanes begin to move | |
| 3 | 7-10 | Gentle Breeze | Large wavelets, crests begin to break, scattered whitecaps | Leaves and small twigs constantly moving, light flags extended | |
| 4 | 11-16 | Moderate Breeze | Small waves 1-4 ft. becoming longer, numerous whitecaps | Dust, leaves, and loose paper lifted, small tree branches move | |
| 5 | 17-21 | Fresh Breeze | Moderate waves 4-8 ft taking longer form, many whitecaps, some spray | Small trees in leaf begin to sway | |
| 6 | 22-27 | Strong Breeze | Larger waves 8-13 ft, whitecaps common, more spray | Larger tree branches moving, whistling in wires | |
| 7 | 28-33 | Near Gale | Sea heaps up, waves 13-19 ft, white foam streaks off breakers | Whole trees moving, resistance felt walking against wind | |
| 8 | 34-40 | Gale | Moderately high (18-25 ft) waves of greater length, edges of crests begin to break into spindrift, foam blown in streaks | Twigs breaking off trees, generally impedes progress | |
| 9 | 41-47 | Strong Gale | High waves (23-32 ft), sea begins to roll, dense streaks of foam, spray may reduce visibility | Slight structural damage occurs, slate blows off roofs | |
| 10 | 48-55 | Storm | Very high waves (29-41 ft) with overhanging crests, sea white with densely blown foam, heavy rolling, lowered visibility | Seldom experienced on land, trees broken or uprooted, "considerable structural damage" | |
| 11 | 56-63 | Violent Storm | Exceptionally high (37-52 ft) waves, foam patches cover sea, visibility more reduced | ||
| 12 | 64+ | Hurricane | Air filled with foam, waves over 45 ft, sea completely white with driving spray, visibility greatly reduced |
All you need to know about Medicanes : [Click Here]
How to get the weather forecast in Greece
You should always try to obtain a weather forecast before heading out to sea, especially if you are going more than several miles from shore, as it can be challenging to determine at a glance what winds will appear due to the influence of large land masses, mountains, and other geographical features. You can use your radio, Navtex, or contact the Port Police, who receive weather faxes several times a day for the area.
TELEPHONE
Via the Athens Marine Meteorological Centre's phone line at the Hellenic National Meteorological Service, one can obtain a forecast directly from the forecaster on duty for the specific sea area of interest, on a 24-hour basis, by dialing 210 9699171. General weather forecasts are obtained from a pre-recorded message of the National Telecommunications Organization of Greece (OTE), by dialing 14944.
RADIO
Regular Weather and Sea Bulletins for Shipping, issued by the Hellenic National Meteorological Service, are broadcast by the 1st Program of Hellenic Radio (ERA 1) in Greek, as are special forecasts and warnings whenever issued. The frequencies and times of broadcast are mentioned below:
HELLENIC RADIO (NATIONAL NETWORK) (ERA 1)/DAILY/(AM) 7.29 KHz, (FM) 105.8 KHz, (FM) 91.6 KHz/06:05
TELEVISION
The Hellenic National Meteorological Service forecasts are announced on TV by professional meteorologists from the Hellenic National Meteorological Service, as well as by TV presenters. Greek public and private channels broadcast the weather forecast for the coming day at the end of the news bulletin. In addition, some channels broadcast a special forecast for the entire week.
VHF/OLYMPIA RADIO
VHF channel 16 broadcasts Gale Warnings, as well as regular forecasts, upon request from vessels.
OLYMPIA RADIO broadcasts pre-recorded Weather and Sea bulletins in Greek and English.
MINISTRY OF MERCHANT MARINE RADIO
Hellenic National Meteorological Service forecasts can also be communicated to vessels via any local Port Authority, upon calling local channel 12 or channels VHF 07, 18, 19, 20, and 2, depending on the locale of navigation.