MeteoNews said snowfall could reach as much as 30 centimetres in some locations.
In the canton of Uri, unprepared motorists remained blocked on the road in the Alps between Gösechen and Andermatt on Wednesday morning because of snow.
Cantonal police said traffic was halted because some cars were not equipped with snow tires, according to a report from 20 Minuten newspaper.
In Graubünden, where the forecast highs for many parts of the canton in eastern Switzerland were zero, snow was forecast through the day.
In the town of Leysin in the Vaud Alps motorists struggled to deal with up to 12 centimetres of snow.
Webcams at Verbier, where temperatures dipped overnight to minus five degrees, showed snow falling on the Valais mountain resort on Wednesday morning and at surrounding areas in the 4 Vallées region.
The white stuff is not expected to last for long, however.
Forecasts from MeteoSwiss, the national weather office indicate temperatures will rise to more seasonal levels by the end of the week.