מזג האוויר בליון בספטמבר

Lyon's forum rates September as still genuinely warm — regulars cite 60s to 70s°F as typical, occasionally reaching 80. Temperature forecasts hold up reasonably well a few days out, they say, though rain predictions shift constantly, so checking again close to the date is the standard advice.

Regulars are consistent that spring has genuinely arrived by this point, mild and often sunny days becoming the norm, though a few properly cool, rainy days still mix in and catch visitors who packed only for warmth off guard. Our row backs that mild, still-showery read, 18.1C over 7.8C nights feeling 5C, with 65.9mm of rain across 8.4 days and a trace of very late snow, 0.7cm, reflecting just how variable early April specifically can still run. Regulars are consistent a light rain jacket belongs in the bag regardless of the forecast, since a sunny morning here can still turn to an afternoon downpour. This remains a comfortable month overall for exploring Vieux Lyon and the traboules on foot. The record: humidity 69 percent, 10.3 hours of sun, a 16.5 kph wind and AQI 45.

This is the month the Lyon board stops discussing what to see and starts discussing whether the room has air conditioning. Regulars recall heat waves with days in the thirties and the occasional run at forty, and note that one July can be mild with only a few very hot nights while the next is nothing of the sort. Our row sits at 29.2C reading as 30C at 62 percent humidity, over 17.8C nights, with 54.9mm of rain across 7.1 days and 12.5 hours of sun. The city's saving grace in a hot spell is the same one Paris has - stone buildings, shaded quays and two rivers to walk beside after dark. The record: a dew point of 14.2C, a 14 kph wind and AQI 43.

April, May and June are the season regulars recommend here, and June is the last of them - by July the question on this board stops being what to see and becomes whether the room has air conditioning. Even early June is described as sunny and hot enough that the machines are already running. Our row reads 27.2C over 16.6C with 12 hours of sun inside 15.6 of daylight, so the warmth arrives without the felt temperature running away - 28C rather than more, at 68 percent humidity. What June keeps from spring is the rain, 87.1mm across 10.3 days, mostly as afternoon storms rather than grey days. The record: a dew point of 13.9C, a 14.5 kph wind and AQI 53.

April to June is the season Lyon regulars name, and May is the month they single out for one specific reason: the rose garden in the Parc de la Tete d'Or is magnificent now, which is not something a climate table can show. The city is also not crowded at this point in the year, before the summer arrivals. Our row's 21.6C over 11.7C is comfortable walking weather rather than terrace weather, and the qualification is rain - 89.5mm across 11.5 precipitation days is a wet day in three, so this is a month for a jacket and a museum in reserve rather than a month to plan outdoors and hope. The record: 10.7 hours of sun and AQI 48.