The London Marathon is one of the largest annual sporting events in the UK. More than 36,000 charity fun runners take part, as well as hundreds of professional athletes and youth competitors.
This year's event takes place on Sunday 21 April.
Since the London Marathon began in 1981, more than 830,000 people have successfully completed the 26 mile race.
Last year's London Marathon took place on warm Sunday in April, with temperatures reaching almost 16 °C. What will the weather be like for this year's event?
Check the weather forecast for the London Marathon on Sunday.
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21 April - Will you be cheering on the London marathon competitors? Check the London weather forecast.
Runners will be looking for a fine spring day to help them get around the 26.2 mile course in London. A mild, but not hot, day with a light breeze will help those charity runners who will still be completing the course past noon. Those conditions will also help the professional runners get around the course in world-record time - as we saw in 2002 when Khalid Khannouchi shaved a few seconds off his own world-record.
The event has seen some extremes of weather in the past 10 years. In 2004 it was particularly wet and windy, and Evans Rutto, the eventual winner of the professional men's race, slipped and fell in the poor conditions.
In 2012 Nilson Kipsany from Kenya won the men's race in 2:04:44 which was the second fastest time recorded. This also guaranteed his place in the Kenyan Olympic team for the London 2012 Olympics. In the wheelchair race, Great Britain secured the top spot in both the men's and women's race with David Weir and Shelly Woods winning on home soil.
The London Marathon course passes many of the historic sites of England's capital city. Some of the landmarks runners will take in are:
You can check the weather forecast for other events through the events calendar.
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