Historic March Heat Wave Brings Triple-Digit Temperatures to Southern California: Important Information You Need

Severe Heat Wave Expected in Greater Los Angeles Area

LOS ANGELES – A brief period of cooler weather is set to end as a "large, long-lasting and dangerous" heat wave is forecast to begin Sunday, according to the National Weather Service (NWS). This upcoming heat event is anticipated to be one of the most intense ever recorded for March, significantly elevating the risk of heat illness across the region.

Forecasters have noted that while temperatures on Saturday may range from 6 to 12 degrees above normal due to a brief onshore flow, conditions will drastically shift by Sunday. Highs are expected to climb by 3 to 8 degrees, with coastal areas reaching the 80s and valleys sweltering between 95 and 102 degrees. Certain localities could see temperatures soar to 105°F to 109°F.

Cal/OSHA has responded to the heat warnings by urging employers to implement safety measures for outdoor workers, recommending access to water, shade, and rest breaks as workers may not yet be acclimatized to such extreme temperatures.

Temperature Forecast by County

• Los Angeles:

  • Saturday: 84°F – 92°F
  • Sunday: 87°F – 95°F
  • Notable: Valley areas will be hotter than coastal regions.

• Orange:

  • Saturday: 82°F – 90°F
  • Sunday: 85°F – 93°F
  • Inland areas like Anaheim and Irvine are expected to hit the low 90s.

• Riverside:

  • Saturday: 94°F – 98°F
  • Sunday: 96°F – 100°F
  • Coachella Valley, including Palm Springs, is forecast to approach triple digits.

• San Bernardino:

  • Saturday: 88°F – 96°F
  • Sunday: 92°F – 98°F
  • Cities in the Inland Empire will experience a steady increase in temperature.

• San Diego:

  • Saturday: 78°F – 88°F
  • Sunday: 81°F – 90°F
  • The city itself will stay cooler, while inland valleys may reach the high 80s to low 90s.

• Ventura:

  • Saturday: 80°F – 90°F
  • Sunday: 84°F – 93°F
  • Coastal areas will be milder, while inland locations like Ojai and Simi Valley will be significantly warmer.

Forecast Timeline

• Saturday: Cooler with highs in the mid-70s to low-80s.
• Sunday: Temperatures to rise by 3 to 8 degrees.
• Monday: Coastal highs in the 80s, valleys in the mid-90s.
• Tuesday & Wednesday: Expected peak of the heat wave with valley temperatures ranging from 95 to 102°F.
• Thursday & Friday: Continued dangerously high temperatures, remaining 20 to 30 degrees above normal.

NWS forecasters have labeled this heat wave as "quite possibly one of the top heat wave events for the month of March, ever," warning that the lengthy duration of the warmth significantly impacts vulnerable populations.

Cal/OSHA has stressed the importance of workplace safety, urging employers to provide necessary resources and breaks for employees who may not be acclimated. The agency stated that "employees may need additional breaks and interventions… ensure that employees have shade, water, and rest breaks."

As the region braces for this intense heat wave, residents are encouraged to stay hydrated, seek shade during peak hours, and check on vulnerable neighbors to ensure their safety amidst the rising temperatures.