Mashhad is a year-round pilgrim city, but the climate and the crowd levels vary sharply by season. Spring (April–June) and autumn (September–November) are the most comfortable months: warm but not extreme, with long clear days.
Summer (July–August) is hot and dry; midday temperatures regularly exceed 35°C. Winter (December–February) is cold, with night temperatures below freezing and occasional snow. Pilgrimage peaks at Nowruz (Persian New Year, late March), the birth and death anniversaries of Imam Reza, and during Ramadan; expect packed crowds at the shrine and high hotel prices.