Jamie will be running across Canada during part of their winter, so will encounter Arctic temperatures he has never experienced before.
We took him to Gloucerstershire University's Sport & Exercise Laboratory where they have a chamber in which the temperature can be lowered to minus 20C.
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Rather Cloudy into the evening with light winds, staying mostly dry.
Dryer conditions now and into the evening, possible frosty start to tomorrow.
Fair few showers into the afternoon, light winds and reasonable temperatures.