Seychelles experiences two seasons per year. The north-west monsoon generally lasts from November to April. It is characterised by warm humid conditions, with calm periods interspersed with periods of heavy rain, including occasional torrential downpours. From late-May/early-June to October the islands are subjected to the south-east trade winds – steady winds from the south-east that reach peak strength in July and August. This leads to choppy and sometimes rough seas, making sea transport uncomfortable and limiting the amount of fishing that small boats can undertake.
In 2017 the south-east trade winds began earlier than usual – by the time I arrived in Seychelles on 18 May the SE wind was already steady and the oppressive heat that accompanies the monsoon interchange period had dissipated. We were told that Sooty Terns began nesting early on Bird Island, with the first eggs found on 24 May. Our day visit to North Island on 25 May involved a very choppy outward journey and a sometimes painful return in the afternoon, with the boat rising steeply on to wave crests before crashing violently into the ensuing troughs with spine-jarring force. This situation was not to last, however, for in early May the wind dropped with swings in direction, evidenced by cloud movements, ranging from east to south-west. The sea within the lagoon at Pointe au Sel in south Mahe remained flat calm, as did the sea off Bird Island’s west coast. These were conditions very untypical of the time of year, and even our passages in small boats to Aride and Cousine Islands in early July were uneventful and surprisingly dry.
This unseasonal calm followed a warming of the sea surface tropical western Indian Ocean, not to the extent seen during the strong El Niño of 2015-2016, but nevertheless above the long-term average (http://stateoftheocean.osmc.noaa.gov/sur/ind/wtio.php).
Not until 23 July did conditions return to those of a typical south-east, with strong south-easterly winds on Bird Island and a noticeable
cooling and roughening of the sea. This has been accompanied by the return of large numbers of Lesser Frigatebirds, which up to this time had been present in only small numbers with none seen roosting at night in tall Casuarina trees. Now, the evening skies are full of them, soaring majestically as they prepare for their night’s rest.