Yazd is a desert city and the weather follows accordingly. Spring (March–May) is the best time to visit: temperatures are warm but not brutal, the desert landscape is at its most attractive, and Nowruz (Persian New Year, around 20–21 March) brings the city to life with festivities. Autumn (September–October) is nearly as good — the summer heat has broken and the light is beautiful.
Summer (June–August) is genuinely harsh. Temperatures regularly reach 40°C and above, and the dry air provides little relief. The old city's narrow lanes and underground cisterns help, but sightseeing in midday heat is unpleasant. If you visit in summer, plan to move early morning and late afternoon, and rest during the hottest hours.
Winter (December–February) is cool to cold, occasionally reaching 0°C at night. Yazd rarely sees snow in the city itself, though the mountains are white. A good option for those who want cooler temperatures and thinner tourist crowds.