Seasons & calendars

Where did the names of the months of the year come from? Why are there seven days in a week? And how are seasons defined? Find out all the answers and more here. Plus, find out how calendars vary among different cultures around the world.

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While days and years are (fairly) neat astronomical events, what explains months, weeks, hours and minutes?

Mercury and the Crescent Moon © Ben Fernando, Astronomy Photographer of the Year Young Commended 2009

Observations of the Moon determine the timing of the Islamic year Al Hijra and its months including the holy month of Ramadan. Find out the dates here.

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Why change the clocks, which way should they go, and whose idea was it in the first place? British Summer Time (BST) explained.

Goodbye Sun, Hello Moon © Ariana Bernal, Astronomy Photographer of the Year Young Runner Up 2013

A year on Earth can be split into four as we complete our orbit of the Sun. Each of these are marked by an equinox or solstice.


Whether you are a dragon, a monkey or a rat, Chinese New Year is always spectacular and loud. 


The first day of spring in the UK astronomically occurs on the vernal equinox, 20 March 2019. But did you know there are actually three main definitions for the season coming from astronomy, meteorology and phenology?


Easter falls on a Sunday between 22 March and 25 April, but working out which Sunday exactly requires an astronomical calculation.