In short
Puerto Vallarta is built between Banderas Bay and the Sierra Madre, which gives it immediate relief: the streets in the centre climb, and the jungle starts a few kilometres inland.
From December to March, humpback whales come into the bay to calve. You can see them from the shore, without going out to sea.
What it really costs
The town is dearer than inland Mexico but markedly cheaper than the Riviera Maya, for a wilder coast.
The Zona Romántica and the centre hold the life and are walkable; the large developments to the north require a car or the bus.
What nobody tells you
The rainy season, July to October, is the low season for prices. It rains hard at the end of the day and the vegetation is at its greenest.
The beaches on the south side of the bay — Yelapa, Las Ánimas, Quimixto — are reachable only by boat from Boca de Tomatlán. That is not an excursion but the only access.
The town is one of the most openly welcoming destinations in Mexico for LGBT travellers, and that shapes part of its nightlife.