Porto has a Mediterranean climate with dry warm summers and mild winters.
Over the course of a year, the temperature typically varies from 6°C to 24°C and is rarely below 2°C or above 30°C.
The season remains warm as it gets lots of sunshine. The temperatures usually fluctuate between 15° to 25 °C. Nevertheless, it can rise much higher on the hottest of days, reaching more than 35°C / 95°F at times.
Despite this warm summer weather, the climate rarely feels uncomfortable and oppressive, due in no small part to the relatively low levels of humidity. The summer months in Porto are also extremely dry and rain is most unlikely during this high season. Occasional summer rainy periods may last a few days and are characterized by showers and cool temperatures of around 20 °C in the afternoon, although prolonged sunny periods do take place.
During July and August the regular maximums may stand at mid twenties. Though the Atlantic Ocean provides cool swimming waters, summertime in Porto is really stunning. The beaches are often breezy and typically cooler than the urban areas.
Autumn brings mild yet wet weather in Oporto. The season experiences more comfortable temperature; staying at low 20s for a few days in October it falls dramatically in November. On the other hand, nighttime temperature remains chillier. Moreover, the city receives heavy showers during this season.
During winter, Oporto receives less than five hours of sunshine. With plenty of rainfalls and cold temperature the city becomes calm and cool. The average high temperature falls to 14°C for the whole season while the average low falls to its lowest of 5°C in beginning month of the year. However, the temperature hardly gets down to freezing level.
The rainy season begings in November and usually lasts through January. The wettest month is December with an average of 180mm of rain.
Although the weather in Oporto becomes unpredictable during the spring months it is warm and comfortable. During the season the average high increases gradually; 16°C in March, 18°C in April and 20°C in the last month of the season. The city receives more hours of sunshine as the season progresses.