April through mid-June and mid-September through October are the best months. Temperatures are 20–28°C, the wildflowers are out in spring, and the cruise-ship crowds at Ephesus are manageable. Book a few weeks ahead for the busiest weekends.
July and August are punishingly hot — 35°C and up is normal, with little shade at Ephesus. If you must visit in summer, be at the South Gate when it opens (8 AM) and out by 11 AM, then take a long lunch in Şirince.
November through March is low season — cool, often rainy, but uncrowded. Hotels close some of their rooms and some of the smaller pansiyons shut entirely. The Ephesus site is still open and you can walk it alone, which has its own appeal.
The Selçuk Camel Wrestling Festival in January is a regional spectacle — male camels in season fighting each other in a stadium for one Sunday afternoon, a weird and not-for-everyone tradition that goes back centuries.