The Santa Ana winds, occasionally referred to as the devil winds, are strong, extremely dry katabatic winds that originate inland and affect coastal Southern California and northern Baja California. They originate from cool, dry high-pressure air masses in the Great Basin.
Santa Ana winds are known for the hot, dry weather that they bring in autumn (often the hottest of the year), but they can also arise at other times of the year. They often bring the lowest relative humidities of the year to coastal Southern California, and "beautifully clear skies". These low humidities, combined with the warm, compressionally-heated air mass, plus high wind speeds, create critical fire weather conditions, and fan destructive wildfires.
Typically, about 10 to 25 Santa Ana wind events occur annually. A Santa Ana wind can blow from one to seven days, with an average wind event lasting three days. The longest recorded Santa Ana event was a 14-day wind in November 1957. Damage from high winds is most common along the Santa Ana River basin in Orange County, the Santa Clara River basin in Ventura and Los Angeles County, through Newhall Pass into the San Fernando Valley of Los Angeles County, and through the Cajon Pass into San Bernardino County near San Bernardino, Fontana, and Chino.
The Santa Ana Winds are the sources of most wildfires in Southern California. In most recent times, the winds are known for the cause of the 2025 Los Angeles Fires.