A few to around 5 degrees cooler than Wednesday with the greatest cooling for the Inland Empire. Map of high temperatures for Southern California for Thursday, May 23rd, 2024. A few degrees warmer than Tuesday, around average for the deserts and around 5 degrees below average for the Inland Empire. Highs in the 60s near the coast to the mid 60s to mid 70s for the valleys, in the mid 70s to lower 80s for the Apple and Lucerne Valleys, in the upper 80s to mid 90s for the lower deserts, and in the upper 50s to mid 60s for the mountains for elevations from 4500 to 7000 feet.