Geneva recorded its hottest 23 June on record yesterday, hitting 36, shattering the previous mark of 35.6 set in 2003.
Payerne reached the same level, while Zurich, Chur and Lucerne all climbed past 33.
MeteoSwiss says the run of tropical days will be unusually long, with no real relief expected before the weekend.
Authorities are urging residents to drink plenty of fluids, seek out cool places and check on the elderly as the heatwave shows no sign of breaking.
Swiss Post announce job cuts
Swiss Post will eliminate up to 110 positions in 2027, blaming shrinking letter volumes and fewer over-the-counter transactions
Autumn arrives in Switzerland
The heatwave that has gripped Switzerland since May finally breaks tomorrow
Driver warning in Vaud
Drivers in western Vaud face four nights of disruption on the A1 next week.
Mixed results in school classrooms
Swiss 15-year-olds still rank among the world's best in maths and science, but their performance in reading and maths is sliding
Good news for household bills
Swiss households will pay a little less for electricity next year
Fuel reserves now in use
Switzerland is dipping into its emergency fuel reserves for the first time this year to keep petrol and diesel flowing
