The 2020 California wildfire season, part of the 2020 Western United States wildfire season, was a record-setting year of wildfires in California. By the end of the year, 9,917 fires had burned 4,397,809 acres (1,779,730 ha), more than 4% of the state's roughly 100 million acres of land, making 2020 the largest wildfire season recorded in California's modern history, though roughly equivalent to the pre-1800 levels which averaged around 4.4 million acres yearly and up to 12 million in peak years. California's August Complex fire has been described as the first "gigafire", burning over 1 million acres across seven counties, an area larger than the state of Rhode Island. The fires destroyed over 10,000 structures and cost over $12.079 billion in damages, including over $10 billion in property damage and $2.079 billion in fire suppression costs. The intensity of the fire season has been attributed to a combination of more than a century of poor forest management and higher temperatures resulting from climate change.

The Western United States experienced a series of major wildfires in 2020. Severe August thunderstorms ignited numerous wildfires across California, Oregon, and Washington, followed in early September by additional ignitions across the West Coast. Fanned by strong, gusty winds and fueled by hot, dry terrains, many of the fires exploded and coalesced into record-breaking megafires, burning more than 10.2 million acres of land, mobilizing tens of thousands of firefighters, razing over ten thousand buildings, and killing at least 37 people. The fires caused over $19.884 billion in damages, including $16.5 billion in property damage and $3.384 billion in fire suppression costs. Climate change and poor forest management practices contributed to the severity of the wildfires.