California’s average daily number of coronavirus cases has tripled in the last month, a Times analysis has found, as pandemic conditions deteriorated dramatically around the state.

The coronavirus is now infecting more Californians daily than at any previous point in the COVID-19 pandemic, raising concerns about a new peak in coronavirus-related deaths by Christmas.

As of Saturday night, California was averaging more than 11,500 new coronavirus cases a day over the last seven days, more than triple the number a month earlier, on Oct. 21, which was nearly 3,200, according to a Times analysis.

Even during the summertime surge, which led to the season with California’s worst COVID-19 death toll, the average daily number of coronavirus cases over a seven-day period never exceeded 10,000.

COVID-19 hospitalizations have doubled in the last month, the analysis found. And COVID-19 deaths have suddenly begun to climb in recent days. In the last week, an average of 65 Californian deaths have been reported daily, a more than 50% increase from two weeks ago, when 43 fatalities were reported daily on average.

The rate at which Californians are testing positive for the coronavirus was up dramatically in the last week — a troubling indication of the rapid spread of the highly contagious virus. On Saturday, the coronavirus positivity rate hit 6.1%, double the percentage it was on Nov. 1, when the rate was 2.98%.

On Saturday, San Diego and San Bernardino counties both recorded their highest single-day coronavirus case totals in the history of the pandemic, according to health officials.

Los Angeles County

Saturday continued a disturbing trend of daily case counts surpassing 4,000. On Saturday, 4,387 coronavirus cases were reported, according to an independent Times tally of coronavirus cases; on Friday, 4,158 were reported; and on Thursday, 4,943 were tallied, a single-day record.

If L.A. County averages 4,000 cases daily over a five-day period, officials have said they will plan to require the closure of outdoor restaurant dining areas, which would restrict eateries to serving food only by takeout and delivery for the first time since May. Officials said they plan to give three days’ notice before such a new health order would become effective.

And should L.A. County average 4,500 cases daily over a five-day period, officials have warned that they will impose a springtime style stay-at-home order.

Daily deaths are also starting to climb in L.A. County. On Saturday, an average of 23 residents in Los Angeles County were reported to be dying from COVID-19 daily over the previous seven days; that’s double the figure from early November, when about 11 people were dying a day.

There are a number of reasons for the sudden surge in coronavirus cases in California, where a surge began in late October.

They include the colder weather, which encourages people to stay indoors; increased travel from other harder-hit states; gatherings to watch the NBA Finals and the World Series, won by the Lakers and Dodgers, respectively; Halloween; protests and celebrations related to the election; a general increase in social gatherings; an increase in workplace outbreaks; a premature feeling that the danger of the pandemic had passed; and fatigue and even resentment of continuing with COVID-19 safety precautions, according to state and local health officials.

Cumulatively, California has recorded 1.1 million coronavirus cases and more than 18,700 deaths. Nationally, more than 12 million coronavirus cases have been diagnosed and more than 255,000 people in the U.S. have died.

Federal, state and local authorities are urging people to stay home for Thanksgiving and abandon Thanksgiving travel plans, whether it be a cross-country plane flight or a drive across town, to avoid spreading the virus at celebrations. The virus can be transmitted by people who seem perfectly healthy and never fall sick.

A travel advisory issued by California in mid-November implored residents to avoid nonessential out-of-state travel and asks those who arrive from outside of the state to quarantine for 14 days, meaning they should stay at home or other lodging as much as possible during that time and order food by delivery.

L.A. County’s director of public health, Barbara Ferrer, urged college students living on campus to not return home just for the Thanksgiving holiday. Students who do end up returning home for a month or more, she said, should quarantine in separate rooms for as much as possible for a 14-day period. If they haven’t yet returned home, she advised that it’s too late for them to partake in communal Thanksgiving celebrations, which risks spreading the virus to the rest of the family and friends.

Officials say it’s safest to keep Thanksgiving celebrations just among people in the household. For people who do intend to invite others from outside their household to gatherings, a state health order

COVID-19 has already killed more than double the number of people in L.A. County than died from the flu in the last cold-and-flu season. “This should serve as a severe demonstration of how much more dangerous COVID-19 is than the flu,” L.A. County Health Officer Dr. Muntu Davis said Thursday.

Last week, Los Angeles County issued an advisory urging people to stay home as much as possible for the next two to three weeks. On Friday, a new health order went into effect that ordered nonessential businesses and restaurants with outdoor dining areas to shut their doors to the public between 10 p.m. to 6 a.m.; although takeout and delivery services may continue during those overnight hours.

On Saturday, California’s new limited overnight stay-at-home order went into effect in counties in the most restrictive COVID-19 tier, which covers 94% of California’s population. It’s aimed at being far less intrusive than the statewide stay-at-home order implemented in the spring, and designed to curb late-night drinking and group gatherings, where inhibitions are lowered, masks are taken off and the virus can easily spread.

The order prohibits all gatherings between 10 p.m. to 5 a.m. among people from different households and all nonessential activities outside the home with people from other households.

The order does allow people to leave their homes in the overnight hours to go grocery shopping, pick up takeout food, walk the dog, and work for essential businesses, which includes working for restaurants serving food for takeout and delivery.

Experts say similar government-ordered limits on late-night activity in Europe have helped drive down surges in the coronavirus there.

The surge in cases has been seen across the state. Here is an analysis by region among selected counties in California’s most populated areas as of Saturday night. More detailed analysis for all of California’s 58 counties can be found on The Times’ California coronavirus tracker website