Winters are mild, with average temperatures in January around 9°, and summers are hot but not torrid because they are tempered by the ocean: average temperatures in August are around 25°. The rains are abundant from autumn to early spring, decrease significantly between May and June and are quite rare from June to September. Snow is almost unknown in Porto.
The wind is almost a constant: it blows very strongly in the winter months, while in summer it is a pleasant breeze.
All in all, the best season to visit Porto is spring, when you can enjoy the outdoors without suffering the heat.
Summer is certainly a good season, but keep in mind that Porto is a multi-tiered city and walking up and down steep streets in the hot sun may put you to the test. On the other hand, summer is definitely the best period for those who want to combine a visit to Porto and a few days at the beach in one vacation.
It is also good to remember that the waters of the Atlantic Ocean are cold compared to those of the Mediterranean seas (they reach a maximum of 19 °C in August), so even if the hot days extend beyond the summer it is difficult to bathe from mid-September onwards.
The hottest months of the year in Porto are June, July, August and September, when the monthly average temperature reaches 24 °C, while the coldest months of February and January the thermometer drops up to 6 °C.
In Porto rainiest months of the year are February, October and December during which monthly rainfall average reaches 180 mm. On the other side, driest months are June, July and August when the average rainfall is reduced to 20 mm per month.
August, June and July are sunniest months of the year. During that months, from sunrise to sunset there are 10 total light hours in Porto. In January, November and December daylight hours are reduced to 3.
Months of the year when sea water is warmer are May, June, July, November, August, September and October, average temperature is around 18 °C.
City Card allow you to save on public transport and / or on the entrances to the main tourist attractions.