According to data from MeteoSwiss, the number of tropical nights—nights when the temperature does not drop below 20°C—has increased significantly in the Swiss cantons of Ticino and Vaud over the past decades. This trend is consistent with the broader pattern of climate change affecting Switzerland.
In Ticino, particularly in Lugano, tropical nights have become more common, with several occurrences each summer. Similarly, in Vaud, especially around Lake Geneva, the frequency of such nights has risen, although they remain less frequent than in southern Switzerland.
MeteoSwiss attributes this increase to higher nighttime temperatures, which are a direct consequence of global warming. The phenomenon has implications for public health, as tropical nights can disrupt sleep and exacerbate heat-related illnesses, particularly for vulnerable populations.
Local authorities are advised to consider adaptation measures, such as improving urban green spaces and promoting heat-health action plans, to mitigate the effects of these warmer nights.
