Porto, Portugal's second city, sits in the north of the country on the Atlantic coast where the Douro River meets the sea, at approximately 41.15°N, 8.61°W. It has a warm-summer Mediterranean climate with a strong maritime influence (Köppen Csb) — cooler, greener and considerably wetter than Lisbon — with mild, rainy winters and pleasantly warm, drier summers, reflecting its exposure to Atlantic weather in the humid northwest.

Summer, from June to September, is pleasantly warm rather than hot, with August the warmest month — average highs around 25°C — kept comfortable by cool Atlantic breezes off the ocean, so it rarely becomes as hot as Lisbon or the interior. It is the driest, sunniest part of the year, though the northwest coast can still see cooler, cloudier and occasionally showery spells even in midsummer, and African heat waves are less intense here than further south.

Winter, from December to February, is mild but wet, with January the coolest month — average highs around 14°C and lows near 5°C. The Atlantic keeps hard frost and snow uncommon in the city, so the season is defined more by rain, cloud and wind than by cold, with frequent Atlantic fronts sweeping in off the ocean. Grey, damp days are common, feeding the region's lush green landscapes.

Porto is one of the wetter major cities in Iberia, receiving around 1,200–1,250 mm of rain a year — far more than Lisbon — reflecting its exposure to Atlantic weather in Portugal's humid north. Rain is concentrated in the cooler months from October to April, while summer is comparatively dry. Live rainfall, humidity, and pressure readings for the city are shown in the panels above.

Porto's cooler, wetter, more Atlantic character sets it apart from the warmer, drier Mediterranean south of Portugal, and it is precisely this mild, damp climate — with its consistent rainfall and gentle temperatures — that makes the surrounding Douro Valley one of the world's great wine regions, home to port wine. The city sees markedly less sunshine than Lisbon, and grey, drizzly days are a familiar part of local life outside the summer.

To follow any single measurement in Porto more closely, use our live instruments: the online barometer for atmospheric pressure, the thermometer for temperature, the hygrometer for humidity, the anemometer for wind speed, the wind vane for wind direction, and the rain gauge for rainfall.