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Genève has a continental climate with four distinct seasons — cold winters and warm to hot summers create very different ventilation needs across the year. Summer daytime highs reach 25–33°C, but the key advantage over coastal cities is the temperature swing: nights in a continental climate typically drop 8–12°C below the afternoon peak, creating a genuine overnight ventilation opportunity even after hot days. This daily swing is the foundation of effective passive cooling in Genève.
The classic ventilation technique in continental climates — burst ventilation — is especially effective here: opening all windows wide for 5–8 minutes creates rapid full air exchange without prolonged exposure that cools walls in winter or imports excess heat in summer. This outperforms leaving windows tilted for hours. Winter ventilation requires a brief morning burst: cold outdoor air (typically −5 to 5°C from December to February) is clean and dry and refreshes indoor CO₂ effectively, but extended opening rapidly chills living spaces. Air quality on cold, calm winter days can spike from heating emissions; OpenWindow.live monitors real-time AQI to flag those days.
In Genève, the best ventilation times are typically early morning (5–8 AM) and late evening (after sunset) when outdoor temperatures drop below indoor levels.
Yes, in most weather conditions. Open windows can drop indoor temperature by 2–5°C in 30 minutes if outdoor air is cooler. Check the live recommendation above for tonight.
Above 80% humidity, opening windows can make indoor air feel sticky. Combine with dehumidifier or wait for drier hours.