Southern California is set to experience a substantial rise in temperatures this week, with meteorologists forecasting a significant heat wave to commence on Tuesday and extend through Thursday, coinciding with the first full week of summer.
The National Weather Service has issued an extreme heat watch for the affected days. Downtown Los Angeles and the broader L.A. metropolitan area are expected to reach highs in the 90s Fahrenheit, a notable increase from the 75-degree high recorded on Saturday, the final day of spring. Specific forecasts indicate mid-90s for the San Gabriel and San Fernando Valleys, with potential for temperatures to exceed 100 degrees in the Antelope Valley and the Cuyama Valley in Santa Barbara County. Wednesday is anticipated to be the warmest day of the period.
According to Weather Service spokesperson Carol Ciliberti, the heat wave is attributed to a robust ridge of high pressure centered over Arizona and New Mexico, extending westward over Southern California. Ciliberti emphasized that the elevated temperatures increase the risk of heat-related illnesses, particularly for vulnerable populations such as children, the elderly, and individuals without access to air conditioning. She also advised against outdoor activities like hiking with pets during this period.
This anticipated heat is expected to provide a temporary reprieve from "June Gloom," the characteristic coastal clouds and fog typical for this season, though the marine layer may return later. This forecast follows a period in March when prolonged high temperatures set numerous records across Southern California. The National Weather Service has also cautioned, via an X post, that the approaching heat wave elevates fire risk due to drying vegetation and the potential for tall smoke plumes in valleys and mountainous regions.
Separately, officials extended a health advisory on Saturday due to particle pollution originating from a substantial warehouse fire in Boyle Heights. This advisory is in effect until 12:30 p.m. Sunday. Air quality in central Los Angeles County, the San Gabriel Valley, the east San Fernando Valley, and the northwest San Bernardino Valley is expected to range from "unhealthy for sensitive groups" to "very unhealthy," according to the South Coast Air Quality Management District (AQMD). The AQMD noted that air quality could deteriorate overnight if winds subside and that shifting winds on Sunday morning might direct smoke towards southeast L.A. County, potentially causing visibility issues and ashfall, especially when combined with high humidity.
In response to the air quality concerns, Los Angeles County public health officials have advised residents to avoid strenuous physical activity and remain indoors with windows and doors closed if they detect smoke. The city of Los Angeles has declared a state of emergency and opened a smoke respite center at Pecan Recreation Center, while the county has established a similar facility at City Terrace Park.
