The Moros i Cristians festival at the end of August is the primary reason to time a visit to Ontinyent. The four days of the festival see the town transform and accommodation is booked well in advance. August is also hot — temperatures in the Vall d'Albaida can reach 35°C — but the evenings are lively.
Spring (April–June) and autumn (September–October) are the best times for a general visit: comfortable temperatures, the natural pools at Pou Clar at their clearest, and the town in its everyday rhythm rather than festival mode. Winter is mild but quiet; many restaurants reduce hours.