LOS ANGELES, Calif. — Southern California is being hit by a brutal end-of-summer heat wave, but the soaring temperatures are only part of the problem.
An unusual surge of tropical humidity is making conditions feel more like South Florida than Southern California, creating a combination of heat and moisture that meteorologists and climate experts say is highly unusual for the region.
Temperatures have climbed into the mid- to upper 80s near the beaches, while much of the coast has reached the 90s. Inland valleys have seen temperatures between 100 and 108 degrees, according to the National Weather Service.
The dangerous combination is expected to peak Wednesday, when residents could face some of the most uncomfortable conditions of the heat wave.
For a region better known for dry summer heat, the humidity is making the weather particularly difficult.
Record Humidity Makes California Heat Feel Worse
The moisture accompanying the heat wave has been extraordinary.
UC climate scientist Daniel Swain told that Southern California is experiencing some of its highest humidities ever recorded, with evidence suggesting that this summer could be the most humid on record at some locations.
Dew points have been especially striking.
The National Weather Service reported dew points reaching 76 degrees in many areas. That level of moisture is comparable to conditions found in a tropical forest and can be even higher than what residents might experience during a humid day in Florida.
The NWS considers a dew point of 55 degrees or below dry and comfortable, while readings of 65 degrees or higher are considered oppressive.
With dew points reaching the mid-70s, residents are facing an atmosphere that can make already-dangerous heat feel considerably more intense.
Extreme Heat Warning Covers Southern California
The National Weather Service has issued an extreme heat warning through Thursday for several areas across Southern California.
The warning includes locations such as the Malibu Coast, Los Angeles County Beaches, Catalina and the San Gabriel Valley.
The heat is not limited to one part of the region. While coastal communities are dealing with uncomfortable humidity, inland valleys are experiencing the most intense temperatures, with readings reaching triple digits.
Officials are warning residents to take the conditions seriously, particularly because high humidity can interfere with the body’s ability to cool itself through sweating.
The combination of extreme heat and moisture can increase the risk of heat-related illness, especially for older adults, young children, outdoor workers and people without access to air conditioning.
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Hurricane Marie Helps Fuel Unusual Weather
The bizarre weather pattern is being linked to lingering moisture from Hurricane Marie, combined with a high-pressure ridge that has developed over the region.
Marie had already affected Southern California during Labor Day weekend, bringing massive waves and flooding before the region transitioned into this oppressive heat and humidity pattern.
The leftover moisture is now contributing to an atmosphere that is far wetter than what Southern California typically experiences during late summer.
The high-pressure ridge, meanwhile, is helping keep temperatures elevated, creating the recipe for the unusual combination of heat and tropical moisture.
Northern California Also Faces Dangerous Heat
Southern California is not the only part of the state dealing with extreme temperatures.
A heat advisory has also been issued for the Bay Area, where some locations have approached 100 degrees. San Jose is forecast to reach 96 degrees, while Fairfield could climb to 103 degrees.
Although the exact conditions vary across the state, the widespread heat is prompting officials to remind residents to take precautions.
Health officials are encouraging people to drink plenty of water, take frequent breaks and seek air-conditioned spaces whenever possible.
As California heads deeper into September, residents across the state are being urged not to underestimate the unusual weather. The combination of extreme temperatures and tropical-level humidity can create dangerous conditions even for people accustomed to hot California summers.
Are you experiencing unusually high humidity or extreme heat where you live? Share your local weather experience in the comments.