Don’t forget that this weekend sees Europe switch to summer time.
This Sunday, March 27 at 1am the clocks will move forward one hour with the UK moving on to GMT+1.
Greenwich Mean (or Meridian) Time is the average time that the earth takes to rotate from noon to noon. It is a mean, or average, because the Earth’s orbit around the Sun is not a perfect circle so the length of a day varies with the time of year.
GMT has existed since 1884, when a 25 nations met in Washington and agreed Greenwich would be the world’s Prime Meridian. This was a tribute to the work of John Flamstead and the Royal Observatory, which had seen the rest of the world use Greenwich to set its clocks.
Every place on the Earth is measured in terms of its distance east or west from the Prime Meridian, which itself divides the eastern and western hemispheres of the Earth, just like the Equator divides North from South.