Short answer: whenever you come, bring a windbreaker.
Bozcaada is famous for its wind, but that's a good thing. No oppressive heat or humidity in summer, and the evenings cool down.

Summer (June–September)
Time for the sea, the beach and festivals. The liveliest season. Don't forget sunscreen and a hat.
Spring & Autumn
If you ask us, the island at its finest. No crowds, mild weather, vineyards lush green or at harvest. Perfect for cycling, walking and photography.
Winter
Quiet, windy, the real Bozcaada. For those escaping the crowds.
In other words, every season has its own beauty, it's about what you love.