The first case relating to the COVID-19 pandemic in the U.S. state of California was confirmed on January 26, 2020. A state of emergency has been in place in the state since March 4, 2020. A mandatory statewide stay-at-home order was issued on March 19. As of September 4, 2020, the California Department of Public Health (CDPH) has reported 722,283 confirmed cases and 13,490 deaths in the state.

As of August 21, 2020, California has the highest number of confirmed cases in the United States, but only the 20th highest number of confirmed cases per capita. It has the second-highest count of deaths related to the virus, behind just New York, but only 27th highest death count per capita. Compared to worldwide provinces/subdivisions, California ranks third in total confirmed cases behind the Indian state of Maharashtra, and the Brazilian state of São Paulo.

March 10: Newsom announced 24 new cases of COVID-19 for a total of 157 confirmed cases in the state. Alameda County reported its third confirmed case in the county. The new case is the spouse of the second case, who was a passenger aboard Grand Princess. The new patient had already been quarantined at home and remains isolated. San Francisco reports a new case in a patient who had known contact with a confirmed case, bringing the total number of confirmed cases of COVID-19 in the city to 14 with 89 confirmed cases in the Bay Area. The city announces a ban on large gatherings and relief for small businesses. On September 8, the CDPH reported that the daily statewide new case positivity rate in COVID-19 testing is at 4%, the lowest since May 25.

Education in California has been impacted by the COVID-19 pandemic. For example, while most students in the state have switched to distance learning as a result of the COVID-19 pandemic, thousands of them lack laptops and Wi-Fi. By April 10, 2020, a school of 21 students became the only school in the state to remain open. On March 17, 2020, the California Department of Education provided guidance for K–12 schools: This includes information regarding: Distance learning, resources that support distance learning remote learning guidance, designing a high-quality online course, grading and graduation requirements, and internet access; school meals; Special education; child care and student supervision in the event of a school closure school.

California State University (CSU) system: With 23 campuses, the CSU is the largest four-year higher education system in the United States. On March 17, 2020, CSU issued a response to the COVID-19 outbreak, including that “the CSU is following guidance provided by the Centers for Disease Control and the U.S. Department of State”. The communication also included information regarding a plan for CSU’s 23 campuses to accelerate their transition to online instruction. On May 12, California State University Chancellor Timothy White announced that the CSU system would be offering fall 2020 courses primarily online “with some limited exceptions.” For spring 2020 alone, the CSU system is projecting a revenue loss of $337 million due to the pandemic.

On May 20, University of California president Janet Napolitano told the UC Board of Regents that “every campus will be open and offering instruction” in fall 2020, adding that she “anticipates that most, if not all of our campuses, will operate in some kind of hybrid mode” involving a mix of online and in-person instruction. From the time that UC campuses shut down in mid-March through the end of April, the UC system experienced a $1.2 billion loss due to the pandemic.

In January 2020, California expected a $5.6 billion surplus in the state budget by the time the fiscal year ended on June 30. In May, however, the Department of Finance changed its projection, saying that the state would instead have a deficit of $54.3 billion. Some of this shortfall was caused by expenses for COVID-19 response (an unanticipated $7.1 billion for health programs and an additional $6 billion for other types of responses), but most was caused by the expectation that tax revenue—personal income, corporate, and sales—will be one-quarter lower than originally projected.