Santorini

Santorini is a seasonal island rather than a year-round destination, and that is the fact everything else follows from. A large share of the caldera hotels, the good restaurants in Oia and Imerovigli, and most of the boat operators close somewhere between late October and mid-November, then reopen across late March and April. In January and February the island is quiet in the literal sense: a few thousand residents, a handful of open tavernas in Fira, and cliff paths you will have entirely to yourself.

The season, when it runs, is intense and lopsided. Cruise ships anchor in the caldera and tender passengers up to Fira, which means the crowd arrives in blocks rather than a trickle — on a four-ship morning the cable car queue and the Oia bus are both overwhelmed between roughly ten and four. July and August add the peak of the fly-in market on top of that, plus Greek domestic holidays around the 15th, and Oia at sunset becomes a genuine crush with people standing three deep along the castle ruins.

The sensible windows are late May to mid-June and the second half of September into October. The sea is warm enough by June and still warm in October, everything is open, the wind that makes spring boat trips unreliable has usually settled, and the ship calls are lighter than in the high summer weeks. If your priority is the caldera view rather than swimming, late October is remarkable value — the light is at its best and rates have already halved.