Drought conditions and wildfires in the Pacific Northwest and parts of the Upper Midwest may reduce the vibrancy of fall foliage in those areas. Prolonged drought and extreme heat can stress trees, causing leaves to turn brown or fall prematurely. Additionally, heavy rain, strong winds, or early frost could abruptly end the foliage season in some regions. Warmer fall nights, which have increased by an average of 2.7°F (1.5°C) since 1970, may delay peak color and reduce its intensity in certain areas.