The sun beams down from the perfect blue sky for between 10 and 14 hours a day between May and September and only tiny amounts of rain will fall. The maximum average temperatures in June, July and August are in the high 20s, slightly subdued by the afternoon meltemi winds.
The sea stays warm enough for swimming in October. You may need to wear something with sleeves if eating outside in May and early June or late September and October.
Syros is known to be an island of festivals – and there are a lot held in the summer. From May to October the island uses some of its beautiful neoclassical buildings and churches to stage an almost non-stop series of concerts, theatre performances, dancing, exhibitions, workshops and children’s activities.
There’s a youth dance festival in May and choral and tango festivals in June. July sees the Festival of the Aegean devoted to opera and other festivals for film, dance, guitars, accordions and rebetiko, a Greek blues music made famous by Syros-born bouzouki player Markos Vamvakaris. August is the month for classical music, video art, installations and performance and organ music from a hilltop cathedral overlooking the Aegean Sea. In September there are festivals devoted to animation and urban art, such as graffiti, supported by music and theatre performances.
The Syrathon, a triathlon sports event held in June, sees athletes of all ages taking part in swimming, cycling and running races. The Syros City Trial, when hundreds race around the heritage sites of Hermoupolis, is staged in September.