The temperature at Zurich airport was a very autumnal -1.9C this morning, while in the watchmaking centre of Le Local in canton Neuchâtel, the thermometer read -6C, according to private weather site Meteonews.
Meanwhile, in La Brévine – the so-called ‘Siberia of Switzerland’ – an unconfirmed report suggested it was as cold as -10.7C.
Light frost was also seen in some places on Switzerland's central plateau as clear skies dominated overnight.
And while Monday is set to sunny in many places, with temperatures in the mid-teens, meteorologists are saying the Indian summer, which came hot on the heels of a long summer season, is now definitely over.
Maximum temperatures north of the Alps are set to be around 12–15 degrees in coming days.
Rain and colder temperatures are then forecast for the weekend.
Read also: In pictures - 12 photos that will get you excited about autumn in Switzerland