Participants were evacuated shortly after 8pm from the Expo park site at the city in the canton of Bern for safety reasons, the ATS news agency reported.
A tent housing first aid attendants threatened to overturn on hundreds of visitors but there were no injuries, the agency reported.
Visitors were advised to move toward Bienne’s downtown area.
The wind ravaged a campsite for the festival, ripping apart tents and scattering belongings across a wide area.
It is not clear from reports how people who were to have stayed overnight in the campsite were to be housed.
Billed as Switzerland’s largest popular sporting event, the gymnastics festival involves 60,000 athletes from across the country, with 120,000 spectators, tripling the normal population of Biel.
The festival is also the oldest sporting event in the country, dating back to 1832.
Competition, which got under way on Thursday morning, continues until June 23rd.
Elsewhere, high winds fanned flames after a sawmill caught fire in Orbe in the canton of Vaud on Thursday night.
The Uldry SA mill sustained serious damage but there were no injures, 20 Minutes reported.
Numerous trees were blown down in various regions.
A 22-year-old driver and a 29-year-old passenger were killed when their car struck a fallen tree in Dietikon, Zurich cantonal police reported on Friday.
Two other passengers were injured in the accident, which occurred on Thursday at around 9.30pm, police said.
Stormy weather hit much of western and central Switzerland on Thursday night following an inflow of warm air from the south.
Temperatures rose to 31.6 degrees in Visp in the canton of Valais and 30.6 degrees in Sion, the canton's capital, ATS reported.
Geneva recorded a high of 30.1 degrees.
High winds and grey skies have sent the mercury dropping but MeteoSwiss, the national forecaster, is predicting is predicting increasingly warm weather through the weekend.
On Monday, temperatures are expected to rise above 30 degrees in many parts of the country, with highs of 33 degrees forecast for Valais.