View of a the San Francisco Bay from the Berkeley Hills on August 10, 2021. Credit: Clara Mokri

With temperatures in Berkeley rising into the low 90s Tuesday, the city is under a heat advisory until 10 p.m. and a spare-the-air advisory throughout the day.

Thanks to cooling onshore winds blowing across the Bay, Berkeley has been spared the even more extreme heatwave in Contra Costa County and the East Bay inland, where temperatures are expected to top 100 degrees. Temperatures in Berkeley are expected to drop on Wednesday, topping out at 80. 

The National Weather Service is reporting that monsoonal moisture approaching from the southeast will create a “slight chance of dry thunderstorms” in the Bay Area that could potentially start fires between Wednesday morning and Thursday morning, but the service does not expect to issue a Red Flag Warning.

“In this situation, it is very hot and dry, but we’re not anticipating there to be widespread, strong winds,” said Roger Gass, meteorologist for the National Weather Service. “If there’s a spark, it could just as easily start a fire in these conditions. It would just be less likely to spread rapidly.” 

The spare-the-air alert issued Tuesday throughout the Bay Area means air quality is considered “unhealthy” due to smog from car exhaust and high temperatures, which effectively “cook” air pollutants and cause elevated ozone levels. 

Residents are asked to limit driving alone and work remotely if possible. Additionally, those with preexisting respiratory conditions should be aware that these air quality levels are an asthma trigger and should limit their outdoor activity. 

Since pollution can drift widely, spare-the-air alerts are issued when air quality is expected to be unhealthy in any of the region’s five reporting zones. 

Air quality appears to be in the good to moderate range Tuesday in Berkeley and Oakland, according to the Bay Area Air Quality Management District and to the U.S. Environmental Protection Agency’s fire and smoke map.   

The air quality district’s only monitoring station in Berkeley, located at Aquatic Park, was vandalized around 1 a.m. on Oct. 1, 2021, and has been offline ever since. Aaron Richardson, a district spokesperson, said the station is in the process of being repaired and should be working again by late June or early July. 

Richardson directed Berkeley residents to check readings from the district’s Oakland stations and to monitor the EPA fire and smoke map, which includes data from crowdsourced private sensors.

Tuesday’s alert marks the second spare-the-air day of 2022; the first alert was issued June 10. In 2021, there were 16 spare-the-air days, five due to smog and 11 due to fine particle pollution. In 2020, a record-breaking year, there were 52 spare-the-air days. 

The National Weather Service offers this preparation advice for heat:

  • 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 under any circumstances. This is especially true during warm or hot weather when car interiors can reach lethal temperatures in a matter of 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 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. Heat stroke is an emergency — call 911 if it occurs. 
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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...