Lausanne weather in September

September on Lake Geneva cools as it goes: regulars track highs sliding from about 23C at the start to 18C by the end, with nights from 13C down to 9C, which our 20.1C monthly average sits in the middle of. The date to know is the vendange, the wine harvest in the terraced vineyards above the lake, which falls at the very end of September into early October and usually lands on good weather - and walking those terraces is the month's best outing. Our row is wetter than an autumn postcard suggests, at 127mm across 14 precipitation days under just 9.1 hours of sun, with the 0.8cm in the snow column belonging to the Alps behind rather than the shore. The record: 13.7C nights, humidity 81 percent and a 7.9 kph wind.

Forum posters describe Lausanne as sharing Geneva's general winter pattern but with noticeably less fog, since the wider Swiss plateau and Geneva itself can sit under low cloud for days at a time in December. Posters note it seldom drops below freezing in low-lying lakeside spots like Lausanne, and some winters bring little or no snow at all right in the city center, even though the region's full climate record shows meaningful average December snowfall and a fairly high number of rainy days overall - Lausanne's lakeside elevation runs milder and snow-uncertain compared to nearby higher ground. Posters are enthusiastic about December as Christmas market season, with especially large ones in Basel, Bern, Zurich and nearby Montreux worth combining with a Lausanne base. Posters generally rate December as cold, often grey and snow-uncertain for Lausanne itself, workable and increasingly festive as the Christmas market season gets underway.

Forum posters put early June around 15-25C and call it beautiful without being too hot, though they're quick to flag that Swiss weather is genuinely unpredictable and varies a lot by altitude - expect a real mix of warm sun, rain, and the occasional thunderstorm within the same trip. Layered clothing plus sturdy waterproof shoes are the standard packing call. June draws noticeably fewer crowds than peak summer, though the city's jazz festival dates are worth checking in advance if avoiding a busier stretch matters to the itinerary.