Tenerife is known internationally as the "Island of Eternal Spring" (Isla de la Eterna Primavera). The island, being on a latitude of the Sahara Desert, enjoys a warm, all year round climate with an average of 22° - 24°C in the winter and 26° - 28°C in the summer and sunshine all year round. On Tenerife, there are no periods annually even during the winter months of cold, but neither are there periods during the summer of unbearable heat as there are in some of the Greek islands of the Mediterranean.
The moderate climate of Tenerife is controlled to a great extent by the tradewinds, whose humidity, principally, is condensed over the north and northeast of the island, creating cloud banks that range between 600 and 1,800 meters in height. The cold sea currents of the Canary Islands, also have a cooling effect on the coasts and its beaches and the topography of the landscape plays a role in climatic differences on the island with its many valleys.
The average temperatures, however, can fluctuate between 17-18ºC and 24-25ºC in the winter season. Evidently there are climatic contrasts which do occur on the island, particularly during the winter months when it is possible to enjoy the warm sunshine on the coast and experience snow within just miles, 3000 metres above sea level on Teide. There is also a contrast in climate between different parts of the island at a lower altitude, even in close proximity, notably between the cities of Santa Cruz de Tenerife and San Cristóbal de La Laguna. Santa Cruz generally experiences a warm climate throughout the year with temperatures noticeably greater than at the bordering La Laguna, where frequently it is colder with a greater chance of rainfall.
The north and the south of Tenerife similarly have different climatic characteristics. The windward side of the island receives 73% of all precipitation on the island, and the the relative humidity of the air is superior and the insolation inferior. The pluviometric maximums are registered on the windward side at an average altitude of between 1.000-1.200 ms, almost exclusively in the La Orotava mountain range. However, although climatic differences in rainfall and sunshine on the island exist, overall annual precipitation is very low with some of the summer months often not receiving any days of rainfall. In June and July in particular it is rare to receive any. The wettest season is during the winter, but in December, for instance, an average of five days of rainfall can be expected, and even this is partly attributed to snowfall on Teide.
As an anecdote, it is interesting to note that doctors from northern Europe, mainly English and Dutch, have over the last few centuries, praised the climate of the northern Tenerife, and have even recommended patients to temporarily move there from the south to alleviate ailments and to improve circulation.