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Climate and Environment

An Extreme Heat Wave Is Coming, And Expected To Stay Through Labor Day Weekend

A close-up of a reed-like plant, which is shown in silhouette against the top half of a bright yellow and red sun in the background.
The sun rises behind native fiddlenecks in San Luis Obispo County.
(David McNew
Getty Images)
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A heat wave is headed to Southern California on Tuesday, and is expected to stay in place throughout the week.

By Saturday, Riverside, the San Fernando Valley and the Antelope Valley could reach highs of 110 degrees, and downtown Los Angeles could see temperatures as high as 100 degrees.

The weather will be cooler near the coast, with highs in the 70s and 80s over Labor Day weekend.

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In response to the high temperatures, the National Weather Service has issued an excessive heat watch from Wednesday morning through Sunday.

The warning covers a broad swath of Southern California, from coastal and inland Orange County to the Riverside County valleys and mountains, the San Bernardino County mountains and the high and low deserts.

Fire Risk

The heat wave brings an elevated fire risk.

Robbie Munroe, a meteorologist with the National Weather Service, said the high temperatures will further dry out local vegetation.

"The heat can add instability to the atmosphere, so if we get a larger fire going, it can kind of blow up quicker than it would in a non-heat wave,” he said.

Experts warn that infants and children, those over age 60 and people with certain health conditions are at greater risk during extreme heat incidents, and should be watched carefully for symptoms of heat-related illness.

Those who must be outdoors during the heat are encouraged to stay hydrated and take breaks in shaded areas. Public libraries can also be a place of respite.

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This heat wave is expected to last throughout Labor Day, although some models are showing elevated temperatures in California throughout September.

Safety Tips And Staying Cool

Staying safe in the heat
    • Don't wait until you're thirsty to drink water or electrolyte-replacements
    • Drink cool water, not extremely cold water (which can cause cramps)
    • Avoid sweetened drinks, caffeine, and alcohol
  • Protect a pet from excessive heat

    • Never leave a pet or animal in a garage
    • Never leave a pet or animal in a vehicle
    • Never leave a pet or animal in the sun
    • Provide shade
    • Provide clean drinking water
  • Protect a human from excessive heat

  • Check in frequently with family, friends, and neighbors. Offer assistance or rides to those who are sick or have limited access to transportation. And give extra attention to people most at risk, including:

    • Elderly people (65 years and older)
    • Infants
    • Young children
    • People with chronic medical conditions
    • People with mental illness
    • People taking certain medications (i.e.: "If your doctor generally limits the amount of fluid you drink or has you on water pills, ask how much you should drink while the weather is hot," says the CDC)
Tips to stay cool
    • Kiddie pool
    • Lotions in the fridge
    • Eat spicy foods in the basement (or on the floor) while wearing a damp shirt and listening to the rain setting on your white noise machine
    • Make sure ceiling fans are running counterclockwise
    • Wet paper towels. Fold into ankle and wrist cuffs. Freeze. Wear. Repeat.
    • Build a DIY AC
    • Build a mini cold air fan
    • Build an "evaporative cooler for immediate heat relief"
    • Make a barricade of fans and ice cubes
    • Go to an air-conditioned store and browse for as long as possible (Target is a good option for this).
    • Close all the curtains, preferably the heat-absorbing kind
    • Or open all the windows, depending on the breeze situation
    • Cool bath or shower twice a day
    • Wash your sheets before bed but don't dry them — put them on your bed damp (provided you're dealing with a dry heat)
    • Portable A/C unit

How To Save Energy

How You Can Save Energy
  • Set your air conditioning at 78 or higher. If you can turn it off and use a fan instead, even better. You can pre-cool your house to 72 in the morning hours when there is lower demand on the power system, then when you set it to 78 in the afternoon, it won’t be quite as unbearable.

  • Unplug “energy vampires” -- those appliances that are sucking power from the grid even when they are not being used, like a microwave oven, and phone chargers.

  • Close drapes and blinds to keep your home cooler inside. Turn off unneeded lights.

  • Wait until the early morning or late evening hours to run the washing machine or dishwasher, or vacuum.

  • If you have an electric car, don't charge it in those afternoon or evening hours

  • For those lucky enough to have a pool, do your part by turning off your pool pump.

Get text updates
  • We're taking your questions about September's heat wave. Text HEATWAVE to 73224 to ask us your questions, and to receive our latest news on these outrageous temps, directly to your phone.

What questions do you have about Southern California?