View of the San Francisco Bay from the Berkeley Hills. Credit: Clara Mokri

The National Weather Service has issued an excessive heat watch for Berkeley and western Alameda County beginning Thursday and extending through the Labor Day weekend until Tuesday evening. 

Downtown Berkeley will likely be spared the more extreme heat wave driving thermometers well above 100 elsewhere in the Bay Area. 

Thanks to onshore winds, temperatures in the Berkeley flats are predicted to peak at just 85 degrees Sunday and 81 on Monday, according to the NWS. It will be hotter in the Berkeley and Oakland hills, with temperatures expected to rise into the mid-90s. 

“[The hills are] not getting that influence from the marine layer,” said Alexis Clouser, a meteorologist with the NWS. “So it’s going to warm up a lot.”

The heat wave is driven by a ridge of high pressure moving in from Utah and Nevada.

Evenings will, fortunately, provide a reprieve from hot temperatures in Berkeley, with overnight lows in the low 60s expected throughout the weekend.

The heat wave is expected to end on Tuesday evening, with temperatures Wednesday falling back down to the high 70s. Currently, the NWS is not expecting to issue a red flag warning, as they are not predicting the high offshore winds that heighten wildfire risk.  

The California Independent System Operator issued a Flex Alert Wednesday, asking California residents to voluntarily save power between 4 p.m. and 9 p.m., as hot weather across the state is expected to strain the power grid. Additional Flex Alerts throughout the weekend are also a possibility as record-setting temperatures are forecast across much of the West.

Power lines atop the Berkeley Hills. Credit: Clara Mokri

 It offers this advice for energy conservation before a Flex Alert:

  • Pre-cool home by setting the thermostat to as low as 72 degrees
  • Use major appliances:
    • Washer and dryer
    • Dishwasher
    • Oven and stove for pre-cooking and preparing meals
  • Adjust blinds and drapes to cover windows

During a Flex Alert, the nonprofit overseeing the state’s power grid recommends you:

  • Set the thermostat to 78 degrees or higher, if health permits
  • Avoid using major appliances
  • Turn off all unnecessary lights

The National Weather Service offers the following preparation advice for heat waves:

  • Monitor the latest forecasts and warnings for updates on this situation. Be prepared to drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check on relatives and neighbors. 
  • Young children and pets should never be left unattended in vehicles. This is especially true during warm or hot weather when car interiors can reach lethal temperatures in minutes.
  • Take extra precautions if you work or spend time outside, and, if possible, reschedule strenuous activities to early morning or evening. To reduce risk during outdoor work, the state 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 shady location. Call 911 if someone is experiencing a heat stroke. 

Update, Sept. 1 The California Independent System Operator has also issued a Flex Alert for 4 p.m. to 9 p.m. on Thursday, Sept. 1.

Iris Kwok covers the environment for Berkeleyside through a partnership with Report for America. A former music journalist, her work has appeared in the San Francisco Chronicle, KQED, San Francisco Examiner...