Zandbank Draken

The concept of time and how to meassure it seems to be quite difficult to understand at first, especially the part regarding time zones in combination with daylight saving. However, the figure and explanation below should make understanding it easy.

Neighbouring time zones generally differ by one hour, for example 07:37 GMT (Greenwich Mean Time) is the same time as 08:37 CET (Central European Time) because CET is one hour ahead of GMT.

The term UTC stands for Coordinated Universal Time (the letters just do not match) - all other time zones can be expressed using an offset to UTC. CET for example is one hour ahead of UTC, so it can be called UTC+1 as well. A time zone one hour before UTC can be called UTC-1.

Daylight saving

Besides normal time, which is commonly called "winter time" even though this is not correct, there is summer time as well where daylight saving is in effect. The purpose of daylight saving/summer time is believed to be the saving of energy, as sun raise and dawn are one hour later each so that sun light can be used in the evening for one more hour instead of switching on electrical lighting.

At the transition moment from normal time to summer time, the term GMT (UTC+0) changes to BST (British Summer Time, UTC+1) and CET (UTC+1) turns into CEST (Central European Summer Time, UTC+2). Everything but the one hour shifting stays the same. The change is the other way around when changing from summer time back to normal "winter" time.