Spanish Time is in the Central European Time (CET) Zone, being 1 hour ahead of Greenwich Mean Time (GMT+1).
Like most countries in Europe, Summer Time (Daylight-Saving) is observed in Spain, which make Spain 1 hour ahead of the UK and neighbouring Portugal, and 2 hours ahead of Greenwich Mean Time (GMT+2). Like most countries, this change is usually at the end of May.
After the Summer months the time in Spain Time is moved back by 1 hour to Central European Time (CET) or (GMT+1), at the end of October.
Nowhere else in Europe do people keep such late hours. While not so many Spaniards take a traditional midday siesta as they used to, partly because many work away from home more than in previous decades, their life cycles remain committedly nocturnal. Like everything else, practices differ somewhat by region. Madrid is famed for staying up the latest, with Andalucia a close second, while in the north, particularly in Catalonia, they keep more Northern European hours, mainly dictated by the weather. And, of course, summer nights are the real late, late shows.
You will find that some of parts of Spain, Spaniards consider that morning continue until siesta time, which is often about 2pm, and it is then, or perhaps after siesta (which can anything between 3pm and 5pm), that the afternoon starts. Spaniards don't have an 'evening' as such. Their afternoon extends until night, which, in typical Spanish style, doesn't appear to have a starting time. As for the term 'Midday', it's a vague time somewhere in the day, but rarely at 12 noon, and possibly when the sun is directly overhead.
The Spanish are not 'time-minded'. For example, because a shop or other business has a sign on the door showing opening times, it doesn't mean it will be observed. The owner or staff may well consider they have something more important to do, or they don't expect any customers. In more rural areas it is not unusual to find a shop or business open but unattended, while the owner or staff have a coffee or snack in a cafe across the road.
Appointment times seem to be more of a guide than a fixed time, so are rarely kept on time, and sometimes not at all. Generally, the Spanish people have a very 'switched-off' attitude to time. To them, it doesn't seem to matter. It's a nice relaxed attitude if you can cope with it.