La Mancha has fierce extremes — summer brings 38–40°C heat with no shade on the windmill ridge; winter sees sharp frosts and the occasional dusting of snow. The shoulder seasons are easily best.
April–May is when the plain is briefly green and the wildflowers bloom around the Roman dam. September–November is the most rewarding time, particularly the last weekend of October, when the Saffron Festival fills the town with food stalls and folk dancing. If you only have one day to spare for La Mancha, this is the day.