Almagro is at its best in spring (April–June) and early autumn (September–October), when the weather is pleasant for walking the old streets and the crowds are manageable. Summer in La Mancha is ferociously hot — temperatures regularly exceed 40°C in July and August — so if you come in summer, plan to do your sightseeing in the morning and evening.
The International Classical Theatre Festival (Festival Internacional de Teatro Clásico) runs through July and is Almagro's biggest cultural event of the year. It draws theatre companies from across Spain and beyond; the Corral de Comedias performances sell out well in advance. The festival transforms the town's atmosphere and is worth planning a trip around if you have any interest in Spanish Golden Age drama.