SAN DIEGO - An excessive heat warning was in effect for the fourth consecutive day Monday in the mountains and deserts of San Diego County.
"Hot weather will continue across the inland areas through (Monday) under a strong ridge of high pressure," according to the National Weather Service. "Some high clouds may moderate temperatures a bit, but it will still be dangerously hot."
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The agency said the deserts will experience higher humidity Monday, making it even more uncomfortable as temperatures soar into the triple digits.
Highs in the deserts Monday are expected to range from 107 to 113 degrees. For mountain areas below 5,500 feet, Monday's highs are expected to be mostly in the 90s.
"Exceedingly high temperatures can cause heat-related illness or death," the NWS said. "Those working or playing outdoors, the elderly, the young and those with existing health conditions, as well as those without air conditioning, are most vulnerable."
Elsewhere in the county, Monday's highs are expected to be in the mid-70s at the beaches, mid-80s inland, mostly high 80s in the western valleys and mid-90s near the foothills.
The excessive heat warning for the mountains and deserts is scheduled to end at 8 p.m. A slow cooling is expected through the week.