This weekend two major marathon events will take place – one in Vienna and the other one in London. In Vienna it will be the 34th Vienna City Marathon and in London the famous Virgin Money London Marathon will take place. The marathon season has begun! Weather plays an important role in running and can influence the personal results for each runner.
The forecast for the London Marathon this Sunday is pleasant. The sky will be mainly covered with clouds, but the sun comes out sometimes. It will be dry and the temperatures are around 7 degrees at the start and 12 degrees in the afternoon. The wind is moderate, so it should be no problem for the runners.
In Vienna the situation is a little bit different. The marathon will take place in slightly changing weather conditions: sun, clouds and short rain showers are possible. The runners must also adjust themselves to partly strong northwest wind. The temperatures will be between 6 degrees at the start and 11 degrees at the finish line.

Rain or sunshine?
Rain ensures that the air is clean and that pollen and dust are removed, making breathing for those with allergies easier. Rainfall is often a welcomed way of cooling down, especially during hot summer days. However, in the event of heavy rain it is possible that shoes and clothes become soaked as soon as you step outside. This can, and does, lead to “summer colds” and/or the formation of blisters. Furthermore, risk of injuries and falls increase due to slippery surfaces caused by wet weather. When the sun is shining, there is nothing to prevent a relaxed and successful running session. Allergy sufferers however have to prepare themselves during the pollen season, and everyone should not underestimate the danger of sunburn during long, hot and sunny running sessions.

Hot or cold?
During hot temperatures the body wants to cool down and thus sweats more. When it’s cold the body must heat the inhaled air and the air around the body, both consuming additional calories. You can actually notice this process as you can physically feel your body becoming fatigued far more quickly during extreme sports in cold temperatures.
Nevertheless, very hot weather is almost never ideal for running. Because of the high temperatures the body loses a lot of water during a running session, which must be compensated by drinking plenty of fluids. However, the body loses not only liquid when it sweats, but also minerals such as magnesium and iron. Circulation problems and heat strokes are also real dangers, caution is recommended!

During cold weather, the body has to work harder to stay warm. This burns more calories than in hot weather. However, when the temperatures are very low the risk of hypothermia (= subcooling) increases.
Wet or dry?
High humidity increases the difficulty for the body to cool itself, due to slower evaporation of sweat. You might also have to consume more liquid, which can have a negative impact on your running performance. High humidity in combination with moderate temperatures makes it much warmer than it really is. In the vicinity of large bodies of water, as well as immediately after rainfall, humidity levels are particularly high.
Windy or not?
A lot of runners underestimate the impact the wind can have on their running seasons. Strong and gusty wind isn’t only strenuous, but also reduces the average speed. In addition, those who run against the clock will lose a few seconds and will finish the marathon more exhausted.
Optimal temperature
According to a study, the optimal temperature for a marathon for men is 10 °C and for women 11 °C. During the world record marathon by the Kenyan Dennis Kimetto in 2014 in Berlin (2:02:57 hours), the running conditions were almost perfect: plenty of sunshine, hardly any wind and just 10 °C at the start, at the finish line two hours later the temperature increased to 15 °C. Sprinters, on the other hand, prefer it somewhat warmer: the best times were set at around 23 °C in the 100m sprint.

Be sure of what weather to expect during the marathon and prepare yourself accordingly with our Morecast app. Don’t have Morecast yet? Download it here and have fun!