ジュネーヴの月別の天気

Geneva forum threads describe January as cold and frequently foggy, with typical temperatures cited between 0-4C and many nights dropping below freezing. Posters consistently flagged the low-lying winter fog, common anywhere between November and March, as the defining feature of the season - it settles over the plateau making the city look moody and atmospheric, and while it does clear on some days, it can also linger for stretches. A recurring silver lining: the fog typically tops out around 1000m, so a day trip up into the surrounding mountains often means climbing straight out of the grey and into genuine sunshine above the cloud layer. The consistent packing advice was proper winter layers, a warm hat and gloves, plus waterproof boots for anyone heading into snowier terrain nearby.

Regulars are specific that anyone heading up to mountain areas above roughly 2,500 meters should still pack a thick sweater and warm layers, temperatures there capable of sitting at or below freezing even as the city itself runs mild. Our row backs that mild, genuinely wet read, 20C over 8.7C nights feeling 7C, with 78.4mm of rain across 10.4 days and a trace of very late snow, 1.1cm, reflecting those higher-elevation totals. Regulars are consistent this month stays genuinely changeable in the city too, some visitors reporting surprising highs near 30C on an unusually warm stretch while others needed air conditioning indoors and a coat outdoors within the same week. Layers covering a wide temperature range remain the standard advice regardless of which version of the month arrives. The record: humidity 75 percent, 10.5 hours of sun, a 10.7 kph wind and AQI 43.

Geneva's forum calls early June an excellent window — long days, warm without being oppressive, the countryside in full bloom. Regulars flag Lake Geneva's swimming temperature as weather-dependent day to day: a run of sun gets it into the low 20s°C, an overcast stretch keeps it cold.

July here runs in the mid to high twenties with the occasional record-breaking day in the mid thirties, and regulars say the breeze off the lake is what makes the city bearable when it is hot. Our row gives 28C reading as 30C with only 56.4mm of rain across 6.5 days and 12.3 hours of sun. The lake is the other half of the answer and our columns do not carry it: the board puts the water at about 19 to 20C in midsummer, cold and fresh rather than warm, with the Bains des Paquis the swim everyone names. Nights fall to 15.2C, which is a jumper on a terrace. The record: humidity 70 percent, a 10.1 kph wind and AQI 39.

August in Geneva is hot and, regulars note, has been getting hotter - one recent year had a fortnight from the 13th to the 26th with every daily maximum above 25C and a peak of 34.5C. Our row's 27.7C reads as 29C. What makes the city liveable in it is the lake: thousands swim every day, the Bains des Paquis is the name everyone gives, and the water sits around 19 to 20C in midsummer. The breeze off it matters as much as the swim does. The fixture is the city's festival in the first fortnight, with lakeside attractions and one of the world's largest firework displays on the second Saturday. Pack summer clothes plus a jumper for the evenings. The record: 14.7C nights, 7 precipitation days carrying 55.3mm and 11.4 hours of sun.

Regulars say September here can be as warm as summer or carry the first tang of autumn, and that the two arrive at different heights: the grass is browning off up in the mountains while the plain is still summery green. Our row sits between at 22.2C days over 10.9C nights. What the month buys is access - from about mid-September the crowds thin and everything in the mountains is still open - and the vineyard paths above the lake are what they recommend walking. Anyone coming for colour is early: they put the peak between the 20th of October and the 5th of November. Our 70.8mm falls across 8.2 days. The record: humidity 77 percent, 9.3 hours of sun and AQI 39.

Geneva forum regulars are specific that the city itself, unlike the nearby mountains, rarely holds onto a snowy scene: “snow in the city is extremely unlikely (though not unknown), and rain is much more likely,” with daytime highs “between 4-5°C and about 10°C.” When snow does fall in town it “rarely remains,” a different story from the surrounding areas where regulars note it usually melts within days but gets cleared fast from main roads regardless. The Christmas Market on Place de la Fusterie runs from late November through December 24th, and an ice rink stays open all winter on the Rhône riverbank — reliable plans whatever the sky does. Our record: 6.8°C days, 1°C nights, 186.1mm of rain, 17.6 rain days and 36.9cm of snow across the month — a higher snow total than the 'rarely sticks in the city' framing implies on its own, though a monthly average can be pulled up by a handful of snowy years without any single short visit necessarily seeing it accumulate.