The Seychelles offers excellent wind and weather conditions for sailing.  There are two distinct monsoon seasons, each separated by a month of variable inter-season weather.

Between May and October, almost constant winds blow from the south east during which period you can usually expect clear skies.

The winds drop in November and give way to north westerly winds.

The south-easterly wind pattern returns in April. In between these two periods of south easterly and north westerly winds there are two short periods of calm or light winds.

April and May are the sunniest months with a daily average of around 8 hours of sunshine and average air and sea temperatures of 28° to 32°C.  These are warm sea temperatures which makes Seychelles very comfortable for snorkelling, diving and other water sports.

The cyclone season which hits the Indian Ocean further south does not exist in the Seychelles, so winds rarely exceed speeds of 30 knots.

Month by Month

January to March: north westerly winds are dominant with short spells of wind from the north or north east. Speeds between 10 to 15 knots, small swell. In March winds begin to weaken.

April and May: winds blow from north/east with speeds between 5 to 15 knots. Very calm seas with average air temperatures of 32°C and sea temperatures of 30°C.

June: south easterly winds predominate with speeds between 10 and 20 knots.

July to September: dry season, air and water temperature at 28°C, very few rainfalls. South-easterly winds predominate at a steady 20 to 25 knots. Sea can be choppy and some anchorages are not accessible during this period.

October and November: Winds and swell decrease progressively producing what is often some very good underwater visibility. As November progresses the north west winds return.
 
December: winds blow from the north west with speeds between 5 and 10 knots. Temperature rises.

Tides

Tides are semi diurnal and asymmetrical with a gap of about 6 hours between high tide and low tide. The tidal range in the Inner Islands is around 1.80m during spring tides and 1.40m during neap tides.  One of the greatest tidal ranges is at Aldabra atoll where you can expect a range of 4 metres.  Tides give rise to currents which can be quite strong in the straits between islands or in the channel leading to lagoons. There can also be a considerable difference in height between the two daily high tides.

Sea conditions

Throughout the equatorial zone of the Indian Ocean the swell is generally moderate. Waves are usually between 1 and 1.2 m.  Wind currents of between 0.4 to 0.8 knots can be expected amongst the Inner Islands on the Seychelles Bank.  In open sea these currents will usually be between 0.5 – 1.5 knots.

Upwellings can create choppy seas as well as highly nutrient rich waters for marine life.  The south of Mahe island is a good example of this where during the late south east monsoon whale sharks, manta rays, devil rays and large shoals of fish can often be seen from a low flying microlite in choppy waters in this area.

Mooring and Anchoring

Mooring buoys are available in many locations – in particular around north-west Mahé, north-east of Praslin and a few of its surrounding islands.  These should be used wherever available to minimise potential damage to marine life, but where unavailable anchoring is required. Good sand bottom anchorages with depths of 5-8 metres may be found in most of the desired overnight areas. In line with Seychelles’ eco-friendly policies, ANCHORING ON CORAL IS STRICTLY FORBIDDEN.

In the Outer Islands that lie between 130 miles and 630 miles from Mahé, navigation is more difficult due to the presence of low-lying coral reefs and other hazards. The mooring grounds of many Outer Islands are less sheltered and the waters between them less frequently sailed.

Self-skippered sailing is allowed during daylight hours only and you will need to be moored or at anchor by nightfall.

Special Zones have been designated around areas or foul ground, underwater pipelines and cables and areas of special interest or security where care with anchoring and access to the beach are required.  In Beau Vallon Bay on Mahé, there are zoned anchorages and access channels around designated swimming areas.