Does weather affect the results of the London Marathon?

Every year runners descend on London, England for the annual London Marathon. Can weather change the race? In this blog we investigate whether London Marathon finishing times vary with the weather.

Were previous marathons affected by weather?

First, let’s take a look at the previous results and if they were affected by weather. Here I have populated the weather conditions for each of the marathons for the past 21 years using the Visual Crossing Weather Data. In addition, I have included the winning time for the men’s and women’s race and the overall average finishing time for all competitors from the data found at

Temperatures and Past results of the London Marathon (credit:

From the data, race day temperatures vary from a low of to a high of 9C to 23C. This is quite a range of temperatures! How does that affect the race times?

The average race time ranges from 4 hours 20 minutes to 4 hours 50 minutes. Could that be dependent on weather? Here’s a graph of average race time against temperature. There is a strong correlation between the temperature on race day and the average finishing time. As temperature increases, so does the average race time.

Average London Marathon Finish Time by Temperature (degC)

It is possible that warmer temperatures attracts additional entrants. To verify this, we also plotted the number of race finishers against temperature:

The chart suggests there is very little correlation between race day temperature and number of finishers (which is likely given entrants will have trained for long periods of time!)

Are Winning Marathon Times Affected by Temperature?

Now let’s look at how winner’s times are affected by weather by comparing the temperature with the men and women’s fastest finishing times. By simply viewing the data in the grid, we can see that there is a significantly smaller range of values for the winning times. Let’s plot these on a graph against temperature to see how these values correlate.

London Marathon Winning Times by Temperature (degC)

For winners, the correlation is completely absent. Elite runners are not affected by the temperature experienced during the London Marathon – even for 2018, the hottest London Marathon ever.

Using weather data in research and studies

Visual Crossing provides weather data for download and via Weather APIs. If you are interested in using weather data in your studies or research. We offer special academic and non profit plans and discount. Contact support for more information.

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