The Seychelles lies close to the equator and the climate is classically tropical: hot and humid all year round with low annual and daily ranges of temperature. It is dominated by two wind systems, the relatively dry southeast monsoon from May to October and the northwest monsoon which blows from November to April.
Temperatures average 25–30°C at sea level during the southeast monsoon and humidity is about 80 percent. Wind speeds rise at this time of year with very heavy seas around July to September. During the northwest monsoon, the wind speed and direction are less constant and temperatures are up to 3°C higher. Heavy downpours may occur at any time of year, particularly in the granitic islands. Rainfall reaches a peak around mid-December to mid-February.
The islands lie outside the cyclone belt, though in exceptional circumstances cyclones may reach the southern islands. Between the two seasons, when the sun passes vertically overhead, winds may die away completely resulting in flat calm seas and excellent water visibility but very high humidity, particularly around April.
For birdwatching: April – start of the breeding season; May to September – sooty terns nest on Bird Island; October – migration begins
For diving: March to May, September to November – best sea conditions, clear and calm, although diving is good all year
For fishing: October to April, when gentle northwesterly winds blow. But for those with good sea legs, fish are plentiful all year round
For hiking: May to September – drier and less humid
For surfing/windsurfing: June to September – when the strong southeasterly winds blow
Seychelles Ocean Festival (December)
This flagship festival, staged by the Seychelles Tourism Board, celebrates all things to do with the ocean. There are lots of local activities and a popular photography competition.
Seychelles Art Festival (April–May)
Exhibitions by local artists and local and international music performances, Victoria.
Round Table Annual Regatta (July)
A two-day weekend event at Beau Vallon in Mahé with games and sporting events on land and at sea. The boating community gathers offshore, and onshore it's party time.
Feast of the Assumption of the Virgin Mary/La Digue Festival (15 August)
A big day for La Diguois, when the island is lively and crowded with various land-based events, stalls and competitions. Many boats are chartered to visit La Digue for the weekend, and the atmosphere of this normally sleepy island is transformed.
Creole Festival (September)
The biggest event of the Seychelles’ cultural calendar, celebrating Creole traditions with a week of shows, displays and music. Musicians and performers from other countries of the Creole world come to the Seychelles to take part.
Mahé-Praslin Windsurfing Race (September–October)
Race starts from Victoria Harbour and is open to all. Conditions for windsurfing are perfect at this time of year, with fairly strong winds blowing from the southeast.