Staying cool in Milan during a summer heatwave requires a "local" strategy: embrace the siesta and seek the shade. From 12:00 PM to 4:00 PM, when the heat is most intense, you should avoid the sun entirely by visiting air-conditioned museums like the Pinacoteca di Brera or ducking into the cool, marble interior of the Duomo. Dress in light-colored linen or cotton, and carry a reusable water bottle to fill at the city's many "Vedovelle" (green cast-iron fountains) that provide free, chilled drinking water. For a culinary cool-down, indulge in a lemon granita or artisanal gelato. At night, follow the Milanese to the Navigli district, where the canals create a slightly cooler microclimate for aperitivo. If the heat becomes unbearable, take a short train ride to Lake Como, where the mountain breeze and deep water provide a natural refuge that is significantly cooler than the concrete and stone of the city center.