Southern California saw a string of record-warm overnight lows over the weekend. A preliminary National Weather Service San Diego record event report shows that on Oct. 4, Anaheim's low was only 78 degrees, breaking the date's record of 67. Santa Ana held at 77, and San Diego at 74, the warmest low for that date in records going back to 1875.
Those nights matter for health because the body uses cooler hours to recover from daytime heat. When temperatures stay in the mid-70s after dark, people without air conditioning get little relief before the next hot afternoon.
