Coast: late May to mid-June, then September
On the Aegean and Mediterranean — Bodrum, Kalkan, Fethiye, Kas — the sea is warm enough for swimming from late May, and the meltemi wind is settled enough for gulet sailing. June daytime temperatures sit at 26–30°C, sea is 22–25°C, and the high-season crowd has not yet arrived. Late June onwards costs rise sharply. September is our other favourite window: the sea is at its warmest (24–26°C), evenings are still warm enough for harbour dining, and prices drop the moment UK schools go back.
Cappadocia: April–May, late September–October
Balloon flights are the reason most people visit Cappadocia, and balloons need calm winds. April through mid-June and late September through October offer the highest flight-success rates — typically 22–25 days a month. Midsummer (July, August) is hot (35°C+) and surprisingly windy on plateau mornings. Winter Cappadocia is magical with snow on the fairy chimneys, but flight cancellations average 50% in January and February. If you can only travel in winter, build a 4-night buffer.
Istanbul: April, May, September, October
Istanbul has the most forgiving weather window of any Turkish destination. The shoulder months — April, May, September, October — give you 18–24°C days, low humidity, and the cruise-ship crowds either haven't arrived or have left. We avoid August (humid, busy, hotel rates peak) and February (often grey and rainy). Ramadan dates shift each year; if you want Ramadan iftar atmosphere book the last week, but be aware many restaurants change hours.
UK school holiday pressure
British half-terms and the long summer (mid-July to early September) coincide with Turkey's busiest, hottest weeks. Villas in Kalkan and Bodrum book 9–12 months ahead and rates rise 30–50%. Easter and October half-term are sweet spots: weather is good, prices are 20–30% lower, and we can still secure first-choice properties. February half-term is best spent in Istanbul or Cappadocia, not the coast.
Festivals and dates worth planning around
Tulip Festival in Istanbul: early to mid-April. Antalya Film Festival: October. Mevlana whirling-dervish ceremony in Konya: 17 December (the Sheb-i Arus). Major Islamic holidays — Ramadan, Eid al-Fitr, Eid al-Adha — shift annually; many businesses close for 3–4 days during Eid, so we plan around them.