California’s climate is diverse, ranging from temperate coastal regions to arid deserts. Its varied geography contributes to a wide spectrum of weather conditions, including extreme heat. Unique meteorological and topographical features frequently set the stage for intense thermal events.
California’s All-Time Heat Record
The highest air temperature recorded on Earth occurred in California’s Death Valley. On July 10, 1913, the Furnace Creek area registered 134°F (56.7°C). This record was part of an intense stretch of hot weather during which temperatures consistently exceeded 125°F from July 5th to July 14th.
For many decades, a higher temperature recorded in Libya was considered the world record. In 2012, the World Meteorological Organization (WMO) re-certified the 1913 Death Valley reading as the all-time highest, after finding the Libyan record unreliable due to measurement issues. This re-certification established Furnace Creek’s 1913 temperature as the benchmark for extreme heat.
Factors Contributing to Extreme California Heat
Several geographical and meteorological factors combine to create the extreme heat experienced in places like Death Valley. High-pressure systems in the upper atmosphere play a role by acting as a “lid,” which prevents hot air from rising and suppresses cloud formation. This allows intense solar radiation to directly heat the ground surface throughout the day.
Death Valley’s topography exacerbates these conditions; it is a long, narrow basin located 282 feet (86 meters) below sea level. This basin is surrounded by high, steep mountain ranges, including the Panamint, Black, Funeral, and Grapevine mountains. As heated air rises within the valley, it cools and then sinks back down, becoming trapped and creating a self-reinforcing “convection oven” effect. The region also experiences a rain shadow effect from four major mountain ranges, leading to exceptionally dry air and minimal vegetation, which prevents moisture from absorbing or reflecting heat.
Historical Context of California Heatwaves
While the 1913 record stands, California frequently experiences severe heatwaves. Extreme heat is a recurring phenomenon in the state, with numerous notable events impacting various regions. For instance, Death Valley itself has seen temperatures reach 130°F (54.4°C) in both July 2021 and August 2020, though these measurements are still awaiting verification. In June 2013, Death Valley recorded 129°F, marking the highest temperature ever recorded there for that month.
Beyond Death Valley, other areas of California have also endured heat. Palm Springs set a new all-time record of 124°F in July 2024, becoming one of the hottest temperatures ever recorded outside of Death Valley. The 2006 California heatwave was devastating, resulting in over 600 fatalities and widespread hospitalizations, primarily affecting inland counties but also bringing humid heat to coastal areas. In Los Angeles County, Woodland Hills recorded 119°F in July 2006, which was an LA County record, and broke that record again in 2020. Downtown Los Angeles also experienced eight consecutive days of temperatures over 100°F in 1955. These events underscore that extreme heat is not an isolated occurrence but a persistent characteristic of California’s climate, with heatwaves becoming more frequent and severe due to broader climate changes.