Antiparos is emphatically a summer island. July and August bring full tourist infrastructure, reliable sunshine, and the Meltemi wind that cools the heat and drives the windsurfing. This is also the most crowded period — the island is small, and a busy day-trip boat from Paros can noticeably fill the main village. June and September are better: the weather is warm, the water is swimmable (particularly in September when it has had all summer to warm up), and the crowds are thinner.
Outside the summer season, Antiparos is very quiet. Most tourist-oriented businesses close from October to May. The permanent population is small and life moves at the pace of a small Cycladic island in the off-season: peaceful and not necessarily entertaining for visitors seeking activity.