The Paléo music festival is bracing for whatever this summer's weather throws at it, with its own weather station and a meteorologist on site throughout the run.
The Nyon open-air, which draws about 50,000 visitors a day, has drawn up separate protocols for heatwaves and downpours.
In hot weather, water distribution and first-aid staffing are stepped up.
Its "Diluvio" plan for storms involves spreading Chinese-reed straw across the site to soak up mud.
The measures come as Switzerland pushes deeper into its second heatwave in a month.
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