Temperatures in Geneva rose to 39.3 degrees on Thursday afternoon, the highest maximum recorded in Switzerland this year, according to private weather service MeteoNews.
Absolute records fell locally in the cantons of Vaud and Valais.
The previous maximum for this year had been 37.6 degrees, recorded on 11 July in Chur.
The absolute record for the northern Alps in Switzerland, 39.7 degrees, was measured in Geneva in 2015.
A number of local heat records fell on Thursday. In the canton of Vaud, records were broken at Nyon (38.5 degrees), Payerne (38.2) and Mathod (38.2). In Montana, in the Valais Mountains, the mercury rose for the first time to 31.5 degrees, while Sion equalled its August 2003 record with 37.6 degrees.
In northwestern Switzerland, a high of 36.4 degrees was recorded in Binningen in the canton of Basel-Landschaft. The thermometer also hit 36 degrees in Koppigen, Bern canton.
The highest temperature ever recorded in Switzerland was 41.5 degrees, registered in the village of Graubünden, Basel-Landschaft, on 11 August 2003.
