Dangerous heat wave begins in Bay Area; Excessive Heat Warning extended into next week (2024)

FAQs

What is causing the Bay Area heat wave? ›

The heat wave baking large swaths of California is driven by a large ridge of high pressure building over the Great Basin. This is a similar dynamic to what happened in early July, when a ridge of high pressure brought several days of record-breaking heat to California.

By the numbers: In San Francisco, the duration of heat waves — measured as a period of two or more consecutive days when the daily, humidity-adjusted temperatures topped the 85th percentile of historical summer temperatures — has increased by an average of three days since 1961, according to data from the EPA.

The primary reason Californians have been suffering from heat is an upper-level ridge or an upper-level high-pressure system over Southern Nevada and Southern California, said Dave Munyan, a meteorologist with the NWS San Diego. In simplified terms, these ridges allow air to collect and sink.

Climate change, primarily from the burning of fossil fuels, is causing more frequent and intense heat waves (ClimateData.ca 2024).

Death Valley National Park — one of the hottest places on the planet — reached a record high temperature of 128 degrees on Saturday, the Los Angeles Times reported. That's just a few degrees shy of the all-time record of 134 degrees set on July 10, 1913.

July's searing temperatures made it California's hottest month on record, according to national weather data. The average temperature statewide was 81.7°, almost two degrees warmer than the previous record set in 2021. “That is a huge margin,” said Daniel Swain, a climate scientist with UCLA.

Weather. San Francisco enjoys a Mediterranean climate, with average highs hovering in the 60s year-round. Los Angeles sees far more variation, with 80+ degrees in summer and 60s in winter. San Franciscans almost always need layers and light jackets, while Angelenos can get by with T-shirts much of the year.

Towns located in East Alameda and Contra Costa counties are the hottest regions in the Bay Area that are within commuting distance to most cities. The reason is that the mountains that separate them from the East Bay create a barrier for the cool breeze from the water to penetrate inland.

The hottest it's ever been in SF was 106 degrees, which occurred on September 1, 2017.

Already subject to drought, wildfires, and extreme weather, California's environmental and social problems will be exacerbated by a warmer world. Temperatures will continue to rise in coming decades due to greenhouse gases that are accumulating in the atmosphere from transportation, industry, and other human activity.

Why does California feel so hot? ›

Climate change is transforming the character of the West's hottest periods — making them more frequent, more persistent, more humid and more lethal. Greenhouse gas emissions from the burning of fossil fuels also play a role, not only by fueling higher air temperatures but also by warming ocean water.

The highest temperature ever recorded in Death Valley was 134 degrees in 1913. The park came close to breaking the record on July 7, 2024, when temperatures reached a staggering 129 degrees, the highest recorded temperature this summer. It was during a heat wave that baked the West Coast.

The June 2024 heat wave was unusually early and long-lasting compared with typical patterns for the Northeast U.S. It was caused by a large high-pressure system called a heat dome that extended from the ground more than 10 miles up through the atmosphere. A heat dome is both a cause and an effect of extreme heat.

Possible heat exhaustion symptoms include: Cool, moist skin with goose bumps when in the heat. Heavy sweating. Faintness.

The heat wave was triggered by dry conditions and typical seasonal weather patterns. September is often an extremely hot month in Southern California, Nevada, and Arizona, as these regions experience dry, desert-like conditions.

Air pollution in San Francisco comes primarily from transportation emissions, namely vehicles such as cars, motorbikes and trucks, as well as planes, and ships all contributing to the ambient levels of air pollution.

These heat islands form because urban surfaces such as roadways and rooftops absorb and emit heat to a greater extent than most natural surfaces. On a warm day with a temperature of 91°F, conventional roofing materials may reach as high as 60°F warmer than air temperatures.

High waves are increasing due to climate change, with impacts for coastal erosion. JUANA SUMMERS, HOST: Giant waves are crashing along the California coast for the second time in two weeks thanks to stormy weather and high sea levels due in part to human-caused climate change.