Dangerous heat wave hits California, Arizona, Florida and more: What to know

There are hundreds of deaths each year in the U.S. due to excessive heat.

An early season heat dome is bringing life-threatening temperatures to Americans from California to Oregon to Florida.

Temperature records were smashed across the nation on Thursday, including 97 degrees in Cedar City, Utah; 102 degrees in Winter Haven, Florida; 113 degrees in Phoenix; and 122 in Death Valley, California.

On Friday, heat alerts are in effect in seven states: California, Nevada, Arizona, New Mexico, Utah, Texas and Florida.

Temperatures are forecast to soar to a scorching 110 degrees in Phoenix; 109 degrees in Las Vegas; 107 in Tucson, Arizona; 100 in Albuquerque, New Mexico, and San Antonio, Texas; 95 in Dallas and 94 in Tampa, Florida.

The widespread heat will end in the West this weekend but will continue in Florida into Sunday.

Doctors recommend taking excessive heat warnings seriously. There are hundreds of deaths each year in the U.S. due to excessive heat, according to CDC WONDER, an online database, and scientists caution that the actual number of heat-related deaths is likely higher.

Click here for what to know about staying safe in the heat.