After organising your trip to Chamonix for the UTMB®, there are several key aspects of the race itself to understand: the weather to anticipate, fuel and hydration, assistance rules, and sleep management during the event. A solid grasp of these points will help you approach the start line calmer and better prepared.
Weather in Chamonix in August
Late August in the Chamonix Valley generally brings mild weather, but conditions in the high mountains can change quickly and affect both your race kit and hydration strategy during the effort. Recent editions have been a reminder: continuous rain and cold in 2025, and a storm that delayed the start by two hours in 2026. Find our advice on how to prepare in our article Weather in Chamonix in August for the UTMB®.
Fuel and hydration during the race
Knowing where the aid stations are and what you will actually find there will help you plan your breaks and personal nutrition more effectively. Not every station offers the same supplies, and the gap between a checkpoint and a full aid station needs to be planned in advance. Find the details in our article Fuel and nutrition during the UTMB®.
Assistance during the race
The rules on authorised assistance along the course will help you organise meeting points if you have support. Find all the rules, zones and shuttle fares in our article UTMB® assistance: rules, zones and shuttles to know.
Sleeping during the UTMB®
Managing sleep during an event as long and demanding as the UTMB® needs to be prepared well in advance, from the training phase onwards, to get your body used to split sleep on race day. Find all our recommendations in our article Sleep at the UTMB®: how to manage sleep deprivation during the race.
