Porto features a warm-summer Mediterranean climate , with influences of an oceanic climate (Cfb) like the northern Galicia. As a result, its climate shares many characteristics with the warm, dry Mediterranean climates of southern Europe and the wet marine west coast climates of the North Atlantic, providing it warm, dry summers and mild, rainy winters. Cool and rainy days can, occasionally, interrupt the dry season. These occasional summer rainy periods may last a few days and are characterised by showers and cool temperatures around 20 °C (68 °F) in the afternoon. The annual precipitation is high and concentrated in the winter months, making Porto one of the wettest major cities of Europe and the wettest major city with a Mediterranean climate. However, long periods with warmer temperatures and sunny days are frequent even during the rainiest months.
Summers are typically sunny, with average temperatures between 16 and 26 °C (61 and 79 °F), but can rise to as high as 38 °C (100 °F) during occasional heat waves. During such heatwaves, the humidity remains quite low. Nearby beaches are often windy and usually cooler than the urban areas. Summer average temperatures are a few degrees cooler than those expected in more continentally Mediterranean-influenced Portuguese cities because of the oceanic influence.
Winter temperatures typically range between 6 °C (43 °F) early in the morning and 15 °C (59 °F) in the afternoon, but rarely drop below 0 °C (32 °F) at night. The weather is often rainy for long stretches, although prolonged sunny periods do occur.