UCLA researcher Alex Hall say the increase will triple the number of extremely hot days in the downtown area and quadruple the number in the valleys and at high elevations.
The study was conducted with funding and support from the city of Los Angeles in partnership with the Los Angeles Regional Collaborative for Climate Action and Sustainability, a UCLA release said Thursday.
"The changes our region will face are significant, and we will have to adapt," Hall said.
"Every season of the year in every part of the county will be warmer," Hall said. "This study lays a foundation for the region to confront climate change. Now that we have real numbers, we can talk about adaptation."
Although warming with climate change is generally expected, this is the first time policymakers in the Los Angeles area have precise information on which to base their plans, officials said.
"UCLA's model shows projected climate changes down to the neighborhood level, allowing us to apply the rigor of science to long-term planning for our city and our entire region," Los Angeles Mayor Antonio Villaraigosa said. "With good data driving good policies, we can craft innovative solutions that will preserve our environment and enhance the quality of life for the next generation of Angelenos."