Heat Wave to Peak Wednesday, Pasadena Expected to Top Out at 102°

The Pasadena area is bracing for another day of sweltering temperatures as an early-summer heat wave reaches its peak on Wednesday, with officials warning of potential health risks and urging residents to take precautions.

An excessive heat warning issued by the National Weather Service remains in effect until 9 p.m. Thursday for the San Gabriel Valley.

In affected areas, temperatures are expected to reach dangerous highs of 98 to 108 degrees Fahrenheit—Pasadena will likely reach 102.

“Dangerously hot conditions” are forecast, with warm overnight temperatures providing little relief from the heat, according to the weather service. The persistent high temperatures are expected to “increase significantly” the risk of heat-related illnesses.

The South Coast Air Quality Management District has also issued an air quality alert due to elevated ozone levels, which will remain in place until 7 p.m. Wednesday. The combination of extreme heat and poor air quality poses additional health risks, particularly for sensitive groups.

“Ozone air pollution can cause respiratory health problems, including trouble breathing, asthma attacks, and lung damage,” the air quality management district stated. “Children, older adults, and people with asthma or COPD may be more sensitive to the health effects of ozone.”

Officials are telling residents to take precautionary measures to protect themselves from the heat. The National Weather Service recommends drinking plenty of fluids, staying in air-conditioned spaces, and avoiding sun exposure. Residents are also urged to check on relatives and neighbors who may be vulnerable to the extreme conditions.

The weather service emphasized the dangers of leaving children or pets unattended in vehicles, stating that “car interiors will reach lethal temperatures in a matter of minutes.”

For those who must be outdoors, experts suggest wearing lightweight and loose-fitting clothing and limiting strenuous activities to early morning or evening hours. The Occupational Safety and Health Administration recommends that outdoor workers take frequent breaks in shaded or air-conditioned environments.

To help minimize ozone pollution levels, residents are encouraged to limit the use of gasoline-powered lawn equipment, conserve electricity, delay trips to gas stations, and use household chemicals until evening hours.

A gradual cooling trend is expected to begin on Thursday, but temperatures are forecast to remain above normal. Despite the slight relief, officials caution that the heat’s impacts may linger.

Authorities reminded the public to never leave pets or children inside vehicles on days that are even a little warmer than normal, as locked cars can turn into death traps in mere seconds.

“Although it’s crucial that we take care of ourselves, it’s equally important that we extend our hand to those in need. We must look out for those who are more likely to get ill due to the heat, including the elderly, unwell, pregnant women, children, and those living alone,” Los Angeles County Health Officer Dr. Muntu Davis said.

“Hot days aren’t just uncomfortable — they can be dangerous. However, if we make sure to stay hydrated and keep cool, we can protect ourselves and our loved ones, friends, and neighbors. If you have an elderly or unwell family member or neighbor, check on them regularly to ensure they are safe and well,” Davis added.

Where is the latest forecast for Pasadena from the National Weather Service as of 3:43 Wednesday morning:

Today: Sunny and hot, with a high near 102. Calm wind becoming south southwest around 5 mph in the afternoon.

Tonight: Clear, with a low around 67. South southwest wind around 5 mph becoming calm in the evening.

Thursday: Sunny and hot, with a high near 102. Heat index values as high as 105. Light and variable wind becoming south southwest 5 to 10 mph in the afternoon.

Thursday Night: Patchy fog after 11 p.m. Otherwise, increasing clouds, with a low around 67. South southwest wind 5 to 10 mph becoming light and variable in the evening.

Friday: Patchy fog before 11am. Otherwise, partly sunny, with a high near 92. Calm wind becoming southwest around 5 mph in the afternoon.

Friday Night: Patchy fog after 11pm. Otherwise, mostly cloudy, with a low around 64.

Saturday: Patchy fog before 11am. Otherwise, mostly sunny, with a high near 91.

Saturday Night: Partly cloudy, with a low around 63.

Sunday: Sunny, with a high near 88.

Sunday Night: Mostly clear, with a low around 61.

Monday: Sunny, with a high near 88.

Monday Night: Partly cloudy, with a low around 60.

Tuesday: Sunny, with a high near 87.