Spain will do the change of time in the autumn of 2018 certainly for the last time after the decision of the European Union and the agreement of the different countries to stop this change in 2019.
This after the passage on summer time 2019.
The time change will occur on the night of Saturday 27 October to Sunday 28 October.
At 3 o'clock in the morning on Sunday, October 28, it will be 2 o'clock in the morning, just one hour.
You will have 1 hour more sleep between summer time and winter time.
Difference in the Canary Island
Of course, to make it simple, even if it will not affect you, there is a slight exception: The Canary Islands will spend the winter time on the same date, Sunday, October 28 but it is at 2 o'clock morning it will be 1 am!
Why this difference with the Canary Islands
There is a constant time difference between the Canaries and the rest of Spain of 1 hour.
Indeed when it's 11 am in Barcelone, Cadiz, Sevilla and Madrid, it's 10 am in the Canaries.
So to make the transition to winter time at the same time throughout the Spanish territory, it is necessary that this passage takes place "one hour before" in the Canary Islands.