If you want to see Porto at its most extroverted, come during the Festa de São João (late June) and be prepared to fend off attacks from locals wielding plastic mallets. Then stick around for the Regata dos Rabelos, when traditional wooden port boats sail down the Douro River.
Weather in Porto takes the best of the Mediterranean (warm, dry summers and mild winters) and moderates it, thanks to the city’s position near the Atlantic. Even the warmest month, August, only averages a pleasant, not-too-muggy 77 degrees. Though heat waves can push temps up to 95, there’s almost always a decent breeze coming in off the ocean. If you’re looking to relax by the sea, remember that Porto’s beaches can be windy—and are often cooler than the city itself. And during the worst heat waves, nearby forest fires can make the air hazy, obscuring coastal views.
Winter often sees daytime highs in the 50s, but it can be rainy. Porto gets twice as much precipitation as Lisbon. It starts falling in September and doesn’t taper off until February. Sure, there are stretches of sun, but count on using your umbrella.