Porto, in northern Portugal, is notably wetter than Lisbon further south, averaging around 1,200 mm (about 47 inches) of rain a year thanks to its exposure to Atlantic frontal systems moving in off the ocean, with the wet season running roughly October through March. The Douro river, which the city sits along, has a history of flooding during periods of sustained heavy rain across its wider watershed, though the historic riverside district has adapted over generations to periodic high water. Rain here tends to fall as sustained moderate showers rather than short violent bursts, in keeping with the broader Atlantic-influenced climate of northern Portugal. Because prolonged rain is more the pattern than sudden downpours, radar is useful for judging exactly when a band of heavier rain will pass through. Portugal’s IPMA operates the national radar network.
Learn more: How Does Rain Radar Work? · Open the full Rain Map