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London marathon

Can the Met Office help protect your event?

Marathon runners

Planning an outdoor event? Let the Met Office keep you informed of the latest weather in your area.

We supply information to events as diverse as Wimbledon, school sports days, music festivals, motor racing, horse racing or pigeon racing. We can supplement all the information that we supply free of charge, with a bespoke forecast to fully meet your needs and help you work around whatever the weather throws at you.

Contact media@metoffice.gov.uk to discuss how we can help you.

Every April, London hosts the world's biggest road race. More than 30,000 competitors run around the streets of the capital in an often-emotional display of human endurance. The weather conditions are critical to their performance and safety.

In the run-up to the event, our forecasters study weather patterns and send the race organisers forecasts for the days ahead.

In addition, we have provided information on how heat stress can affect the health of participants, allowing organisers to anticipate demand for first aid and drinking stations.

A changing climate

With climate change and a warming trend predicted over the coming years, long-distance runners will have to consider the weather very seriously.

We have worked closely with the marathon organisers on a study looking at the possible future consequences for the event.

Over a 20-year period, looking at April weather in London, we have found that:

  • the absolute maximum temperature (typically mid-afternoon) recorded in April was 25.9 °C
  • the absolute minimum temperature (at any time of day) was 0.7 °C
  • the lowest daily maximum temperature recorded was only 5.1 °C
  • the average daily maximum temperature was 14.4 °C
  • the mean wind speed was 10 m.p.h.
  • the highest daily mean wind speed was 22 m.p.h.
  • the maximum gust was 56 m.p.h.
  • the most commonly occurring mean wind speed was in the range 8 to 12 m.p.h.
  • the wettest April day had 30.3 mm of rain
  • on average there is one day in 10 years with a daily rainfall amount of 25 mm or more
  • on average there are nine days in 10 years with snow or sleet.

Historic weather information

See the table below for weather conditions on marathon days, 1981-2009 (data from London Heathrow, temperatures and rainfall for daytime period 0900-2100).

Weather conditions on marathon days, 1981-2009
Date
Max temp (°C)
Min temp (°C)
Rainfall (mm)
Sunshine (hours)
29 Mar 1981
13.5
10.0
1.3
0
9 May 1982
15.6
10.0
0
8.1
17 Apr 1983
10.2
5.6
5.4
0
13 May 1984
16.6
9.8
0
10.2
21 Apr 1985
11.4
6.6
0
4.3
20 Apr 1986
14.6
6.9
0.1
8.6
10 May 1987
14.9
10.5
0
8.2
17 Apr 1988
17.2
12.0
0
3.2
23 Apr 1989
13.6
6.0
0
0.4
22 Apr 1990
16.1
9.4
0
4.2
21 Apr 1991
11.3
6.7
1.7
4.2
12 Apr 1992
14.3
5.8
0.4
2.3
18 Apr 1993
16.5
11.6
0
4.1
17 Apr 1994
10.2
5.6
0
3.9
2 Apr 1995
19.7
9.0
0
10.2
21 Apr 1996
22.2
15.4
0.1
10.6
13 Apr 1997
17.3
10.1
0
8.5
26 Apr 1998
15.5
9.2
1.8
9.8
18 Apr 1999
11.5
5.5
0
8.6
16 Apr 2000
12.8
7.1
2.0
7.7
22 Apr 2001
11.7
7.3
2.6
4.2
14 Apr 2002
12.1
6.6
0
2.4
13 Apr 2003
18.6
13.1
0
8.3
18 Apr 2004
11.3
5.3
12.4
0.1
17 Apr 2005
15.3
7.7
1.8
9.8
23 Apr 2006
13.6
9.7
1.6
0
22 Apr 2007
22.2
14.8
0
7.1
13 Apr 2008
10.9
6.3
6.6
4.5
26 Apr 2009
17.7
10.9
0
12.3