Cold front arrives on Saturday

Friday, 16 October, opens with patchy fog and low cloud over Switzerland's lowlands, with the fog ceiling near 600 metres. One forecast puts lowland highs at 18 to 22 degrees that afternoon, another at 17 to 20 degrees. On Saturday, 17 October, a cold front arrives from the Jura and western Switzerland, with rain falling first in Basel and the northwest. Forecasters expect the front to lose strength as it moves east, so the eastern Mittelland should see much less rain. Lowland highs on Saturday are forecast at 12 to 14 degrees, while the Alps, Valais and Graubünden stay largely dry and sunny. Meteorologist Michael Eichmann of Meteo News sees the mountains as the best choice for a weekend outing.

“The mountains are the trump card on Saturday.”

Sunday brings heavy rain to the south

On Sunday, 18 October, the main rain band moves to the south side of the Alps. One forecast points to a low forming over the Ligurian Sea, while another describes an upper-level low pulling moist Mediterranean air toward the Alps. Forecasters see the largest totals around the Simplon in Valais, neighbouring Piedmont and the western Ticino Alps, where up to 100 litres per square metre could fall locally within 24 hours. Lowland highs are forecast at 10 to 13 degrees by one outlet, while another expects many places to reach only 8 to 9 degrees. Ticino could reach 16 to 17 degrees, and snow stays above roughly 2000 metres. Eichmann said weather warnings could be issued for the wetter regions on Sunday.

Drought relief and a drier start to the new week

Watson reports that according to MeteoSwiss, much of Switzerland went several months between April and September without rain, so the wet spell arrives at a useful time. Blick says soils and vegetation should benefit from the weekend rain. Eichmann expects eastern Switzerland to stay drier on Sunday, and he said:

“In St. Gallen and Thurgau you probably won't need an umbrella on Sunday.”

Monday, 19 October, is forecast to be milder and mostly dry in many places, although Meteo Schweiz expects stubborn lowland fog with a ceiling near 1300 metres.

Germany expects a cooler, wetter weekend

The German Weather Service (DWD) forecasts cooler weather for Rheinland-Pfalz and Saarland, where Friday, 16 October, stays dry with highs up to 21 degrees and the first rain possible in the Eifel in the evening. Saturday starts overcast and wet, with showers easing later in the day and highs of 12 to 15 degrees. Sunday, 18 October, remains mostly overcast with rain not ruled out and highs no higher than 12 degrees. In Hessen, the DWD expects Friday's highs to stay under 20 degrees, Saturday's to reach 12 to 15 degrees and Sunday's to peak at 12 degrees, with local rain. On Monday, 19 October, rain is still possible mainly in the west, with highs of 12 to 16 degrees in Hessen and 12 to 15 degrees in Rheinland-Pfalz and Saarland.