"It seems like it always happens this way in California that it's not a gradual, it's more of a dramatic effect. So the heat will come as a surprise to some people."

Kelly Huston is with the California Emergency Management Agency. He says California has an average of 20-heat-related deaths a year. That figure skyrocketed five-years ago.

"We saw 140 people die over a 13 day period of excessive heat in California. That was in 2006 and that has led to some really robust plans and preventative measures that we now take today." 

Those measures include swift opening of cooling centers. The California Division of Occupational Safety and Health, or Cal-OSHA, also now requires people who own construction, landscaping and other outdoor worksite companies to protect their workers from heat illness.