Centro Meteo Portugal
The climate of Portugal
Portugal lies in the far west of the Iberian Peninsula between 40 and 42 degrees northern latitude and between 6 and 10 degrees eastern longitude. The country is bordered by the Atlantic Ocean to the west and south and by Spain to the north and east. The proximity to the sea is one of the major influences for the large-scale climate in Portugal. Small-scale differences mainly result from the country’stopography and the north-south orientation of mainland Portugal.
As water reacts slower to warming or cooling than air, the Atlantic Ocean has a balancing effect on land temperatures. Even on a small scale significant differences in temperature can be found in Portugal. Winters are milder on the coast. In January, the coldest month, the average minimum temperature in Lisbon is 8 degrees, whereas in Castelo Branco it is 4 degrees. Maximum temperatures range from 8 degrees in Bragança to 16 degrees in Faro on average. In summer, the opposite effect takes place, as the sea water cools the costal areas. In Viana do Castelo, which is situated at sea level, temperature reaches 26 degrees on average in July. In Bragança they reach 28 degrees, despite the fact that the town is situated at 700 meters altitude. In Beja, in the south of Portugal, average temperatures in July are even up to 32 degrees.
Precipitation in Portugal peaks during fall and winter. In summer, however, extremely dry conditions prevail. In Faro average rain amounts from July to August are only two percent the annual average of 500 liters per square meter! When looking at the spatial distribution of precipitation, one can see that it is much more humid in the north of the country than in the south. While frontal systems from the Atlantic reach the north of the Iberian Peninsula, rainfall in the south is less frequent. For example, in Porto average annual precipitation is 1250 liters per square meter, whereas in Lisbon, 300 kilometers farther south, it is only 720 liters. Mountain ranges in northern and central Portugal like the Serra do Marão or the Serra da Estrela act as weather divide and cause a west-east gradient in precipitation. The backcountry town of Bragança with an annual average of 785 liters per square meter gets only about half the precipitation than Viana do Castelo at the coast.
Madeira as well has a temperate climate due to it’s location in the Atlantic. The coldest month is February with average minimum and maximum temperatures of 13 and 19 degrees, respectively. It is warmest in September, with average highs of almost 26 degrees. Average annual rainfall is 596 liters per square meter, with an average of only 12 liters during summer.
The Archipelago of the Azores is situated further to the northwest, however, temperatures are similar to those of Madeira. In February temperatures drop to 11 degrees and reach 16 degrees on average. August is the warmest month with average highs of 25 degrees. As far as precipitation is concerned, however, there are significant differences: On Flores, the westernmost island, average annual rainfall is 1642 liters per square meter. Farther east, on the island of São Miguel conditions are drier with only 967 liters per year. Fall and winter account for about two-thirds of the annual precipitation.