Spain, physically, is between the GMT and the GMT -1 zone, but during World War II, Francisco Franco, Spanish ruler, changed the time zone to GMT +1 to be coordinated with Germany. Despite being a wartime decision, it was kept and it is today still active.
Repercussions of not living in your natural timezone: siesta
Because of that, in Spain sunset and sunrise are very late and, according to a Subcommittee to study the Rationalisation of Hours, the Reconciliation of Personal, Family Life and Professional Life and Responsibility, is the reason for the late meals in Spain: Spaniards never eat before 2:00 pm, they have the supper ridiculously late, after 9:00 pm.
Because of this, the subcommittee advocates for the standardization of timetables. Not only will avoid strange meal times, but also will help to reconcile work and family life.
Also, because of this late meals, midday meals are often copious, which causes post-lunch drowsiness, the famous Spanish Siesta: a 20 or 30 minutes nap at the beginning of the evening. This nap is also very useful to avoid the hottest part of the day.
Because of Siesta is not a good idea call particular homes before 5:00 pm or even 5:30 pm.
Canary Islands’ case
There are a lot of small parts of Spain that are not in the Iberian Peninsula, being the bigger ones Ceuta, Melilla, Balearic Islands and the Canary Islands. All of them have the same time zone than Madrid, but the last one: Canarian Islands, which are in Africa, in Morocco’s westernmost coast, has an hour less than the rest of Spain. Despite that, they are also not coordinated with solar time: they are in GMT but lives in GMT -1.
If you are listening to the radio in Spain, when they say the time, they usually will tell “una hora menos en Canarias” (one hour less in the Canary Islands).
Learn more about residency in Spain