North and Northwestern Spain is the part of the country which is most influenced by weather from the Atlantic, especially in fall and winter. It tends to be the rainiest and most cloudy part in Spain. Even though summers are colder, cloudier, and wetter than anywhere else in the country, there is still a good amount of warm and sunny weather.
Rainfall tends to decrease from west to east in the Pyrenees, but it is high on the seaward sides of the Cantabrian Mountains and in Galicia. The daily hours of sunshine are on average, three in winter, and eight in summer.
In Central Spain, the rainfall is usually low over the interior, but winter snowfall may be very heavy and sit for a long time on the mountain ranges. In the late summer, most of the country has a dessert like appearance due to the long droughts in the summer. Summers are mostly hot, especially in the Guadalquivir valley, which lies in the south of Spain. There, some of the highest temperatures in all of Europe are recorded each year.
In spring and in the early summer, the weather tends to be the wettest of seasons in many Spanish places, but the rainfall is not heavy and not very efficient for farmers as it usually falls in short, heavy spurts. Winters usually have abundant cold spells and blistering winds coming from the sierras. The dust and hot winds are the worst parts of the summer weather in Spain, but at least low humidity makes the heat more tolerable than in some of the other coastal regions in Europe. Sunshine ranges from an average of five hours a day in winter, to almost as much as twelve hours in the summer.
Mediterranean Spain is an area that includes famous tourist resorts such as: the Costa Brava in the north and the Costa del Sol in the south. Sunshine amounts are high, ranging from six hours a day in winter and up to twelve in midsummer. Winters are mild and much warmer than inland Spain. While summers are hot and can be humid, the afternoon heat is usually chilled by the sea breeze. In the south, conditions can occasionally become nasty when hot, dry wind blows from North Africa.
In most of the region, rain is extremely rare during the months of June through August. However, north of Valencia, the coast is susceptible to occasional heavy thunderstorms in summer. Around Barcelona and farther north, the fall season tends to be wetter than the winter. The total rainfall is greater than in the south, some parts of which are dry. In the drier regions there are major differences in the amount of rainfall from year to year.
The Canary Islands of Spain lie in the Atlantic Ocean. The warmest days during the summer happen when hot, dry air is brought out from the Sahara desert, and makes its way to the Canary Islands. This air may sometimes be filled with fine dust particles that have blown in from the desert. However, it reaches the islands with a higher relative humidity and lower temperatures, due to its passage across the cooler ocean water.
The northern shores of the islands are more exposed to the northeast trade winds, therefore they area wetter than the southern coasts. Daily sunshine hours can range from an average of six hours in winter to as much as eleven hours in the summer. All things considered, the Canary Islands are a crucial part of Spain, and have been occupied by Spain in the 15th century. The weather in these islands is definitely different from the rest of Spain.