00:00California's coast is roasting and the calendar helps explain why.
00:04Record challenging heat will grip the southwest this week with temperatures 10 to 20 degrees above historical average for early
00:10October.
00:11Even the beaches offer little escape.
00:13But look at San Diego's record book.
00:16All 10 of its hottest days happened in September or October.
00:20At downtown Los Angeles, 5 of the 6 hottest days happened in September.
00:24So why can the coast become a fall furnace and why is it typically not a summer sizzler?
00:29In summer, intense desert heat creates an area of low pressure called a heat low.
00:34That helps draw cooler Pacific air inland, reinforcing the ocean breezes that keep you more comfortable at the beach.
00:40Think of it as Southern California's natural air conditioning.
00:44In fall, the interior cools and that heat low weakens.
00:47High pressure can build inland, setting up winds that blow in the opposite direction toward the ocean.
00:52Those offshore winds can overpower the cooling sea breeze and as air descends from the mountains toward the coast, it
00:57compresses and heats up.
00:58Now the natural air conditioning is switched off and the beaches can bake.
01:02So if you're heading to the coast this week, check the AccuWeather forecast.
01:06That ocean view does not guarantee relief as autumn truly is the season when heat can become extreme along the
01:12California coast.
01:12So we're heading to the coast, which is the coast of the coast.
01:13This time it should be the coast of the coast.
