The best months for Pollença are May, June, and September — warm but not hot, the cafés open but the town not yet swamped. July and August are very busy, very hot, and best avoided unless you are coming for the music festival, which is in those months.
The shoulder season around the Easter Davallament procession is one of the most atmospheric times to visit — wildflowers in the Tramuntana, almond blossom in the surrounding villages, and the Holy Week processions through the old town. Winter is mild but most resort businesses in Port de Pollença close until April.