How has temperature changed in California?
• California appears to be slowly warming. Temperatures are increasing most rapidly in Southern California and in urban areas. • Minimum temperatures at night have been increasing at a higher rate than daytime temperature increases. This results in fewer opportunities for the body to cool overnight during heat waves. • “Heat islands” play a large role in the elevated nighttime temperatures. Heat islands are geographic areas that are warmer than surrounding areas. They form as cities replace natural land cover. Pavement, buildings, and other infrastructure retain heat more than natural surfaces. • The number and duration of extreme heat events are expected to increase. This will lead to increases in heat-related illnesses and deaths if precautionary measures are not put in place.
