Authorities are warning of extreme health and wildfire risks across California this week, as the longest heat wave of the year is set to kick off Tuesday, bringing triple-digit high temperatures with little cooling, even at night, to the vast majority of the state.

“This is really just a long-duration heat event that will provide little to no overnight [temperature] relief,” said Antoinette Serrato, a National Weather Service meteorologist in Hanford. The prolonged heat wave is expected to bring dangerous temperatures throughout the Fourth of July holiday weekend in many areas — particularly across Northern California, the Central Valley and southwestern deserts — lasting through early next week, she said.

Much of Los Angeles…