What effect can clouds and fog have on the temperature of a vineyard?

Clouds and fog have a significant impact on vineyard temperature by blocking sunlight, which leads to a cooling effect. When clouds cover the sky, they prevent direct sunlight from reaching the grapes and the vineyard floor, which can result in lower daytime temperatures. Similarly, fog, which consists of tiny water droplets suspended in the air, can also reduce sunlight penetration and contribute to cooler conditions during the day.

This cooling effect is crucial in regions where high temperatures might otherwise negatively affect grape quality. Cooler temperatures can help in preserving acidity in grapes and delaying the ripening process, which contributes to more balanced wines. Additionally, the presence of moisture from fog can benefit the vines by reducing water stress, but the main influence of clouds and fog on temperature is indeed their ability to block sunlight and create a cooler microclimate in the vineyard.