The unusual phenomenon struck central and eastern regions of the country as the wind, carrying warm air from the southwest blew through the plateau and mountain valleys, meteorologists said.
Records for the third week of October were set in in Heerbrugg in the canton of Saint Gallen, where it reached 26.7 degrees, according to MeteoNews.
All-time highs were also recorded in Quinten, also in the canton of Saint Gallen (26.6 degrees), and at Saint Maurice in the canton of Valais (25.4 degrees), MeteoNews said.
Temperatures rose to 26.3 degrees in Vaduz, the capital of neighbouring Liechtenstein, and also surpassed 25 degrees in Rorschach in the canton of Saint Gallen and Flüelen in the canton of Uri, as well as the cantons of Schwyz and Glaris.
Winds were clocked at speeds of up to 105 kilometres an hour on Lake Constance.
SRF Méteo reported that a high of 25.3 degrees was reported at 2am Wednesday at the Altenrhein airport in Saint Gallen.
The winds were expected to subside later in the morning.
Föhn conditions periodically hit Switzerland and other parts of central Europe, warming the climate as moist winds off the Mediterranean Sea blow over the Alps.