The National Weather Service has issued an extreme heat warning for all of Santa Barbara County and much of southwestern California, with temperatures expected to hit 100 degrees in some communities on Wednesday.

The warning will remain active through 8 p.m. Thursday.

Public safety power shutoffs are also possible in parts of South County, according to Southern California Edison.

Up to 6,307 customers along the South Coast could lose power between 3 p.m. Wednesday and midnight on Friday.

Click here to see if your address is under a PSPS warning.

A Community Resource Center has opened at the Residence Inn in Goleta, 6350 Hollister Ave., for those impacted by the power safety shutoffs.

PG&E, which serves North County communities, does not plan any PSPS outages this week.

The area had already been under a heat advisory, with forecasters warning on Monday that temperatures 10 to 20 degrees higher than usual were possible.

There is a high risk of heat illness for “most people” amid the ongoing hot and humid weather, per the Weather Service.

“Heat related illnesses increase significantly during extreme heat events. Hot temperatures may cause heat illnesses,” Weather Service spokespeople said. “Humid conditions will add to heat discomfort. Heat peaking today for most areas.”

High daytime temperatures in the 90s are expected in most communities across the county Wednesday, including Santa Barbara, the Lompoc Valley and the Santa Maria Valley. The Santa Ynez Valley could see even higher temps up to 101 degrees, according to the forecast.

For those working outdoors, the Occupational Safety and Health Administration recommends scheduling “frequent rest breaks in shaded or air conditioned environments. Anyone overcome by heat should be moved to a cool and shaded location,” per the Weather Service.

Check the latest weather forecasts and alerts here.

Public Health Tips to Stay Cool

County officials sent out precautions and tips to stay cool during hot weather:

Do not leave children (and pets) unattended in vehicles. It takes only a matter of minutes on a relatively mild day for a vehicle to reach deadly temperatures.

Drink plenty of cool, non-alcoholic beverages, especially those without sugar or caffeine. Do not wait until you are thirsty to drink. If you have fluid restrictions from your doctor, ask to see how much you should drink while the weather is hot.

Avoid hazardous activities that may cause sparks and start a wildfire, such as using lawn care equipment and towing with dragging chains along roadways.

Take care of those who might not be aware of high temperature dangers or be able to react accordingly — especially the elderly, young children, and pets. Check on your neighbors.

Limit outdoor activity. Try to schedule outdoor activities during the cooler parts of the day, such as morning and evening hours. Be sure to wear sunscreen and rest often.

For those who work outside, be sure to take frequent rest breaks in a shaded area or air-conditioned room, if possible. Stay hydrated and take action by moving to a cooler space if you feel signs of heat exhaustion.

Take regular breaks in the shade or in an air-conditioned room. A few hours in air conditioning can help your body stay cooler. Taking a cool shower or bath can help, too.

If you do not have air conditioning, consider arranging to spend at least parts of the day at another space that is cool. Electric fans may provide comfort, but when the temperature is in the high 90s, they will not prevent heat-related illness.

Wear appropriate clothing. Lightweight, light-colored, loose-fitting clothing works best.

Know the signs of heat exhaustion. If someone becomes dizzy, nauseated or sweats heavily, find a cooler location for him or her immediately.

Know the signs of heat stroke. Heat stroke is much more serious than heat exhaustion. The symptoms are similar to heat exhaustion, but also include hot, flushed skin. With heat stroke, the person often stops sweating and the skin will be unusually dry. If heat stroke is a possibility, call 9-1-1 immediately. Heat stroke is life-threatening!