At 11:30 a.m. Saturday, Americans across the country began turning on their televisions.
Moments after CNN and most major television networks declared that Joseph R. Biden Jr. had defeated President Trump in the presidential election, viewership numbers surged on all three major cable news networks and the three major broadcast networks, according to Nielsen Media Research.
On CNN, viewership jumped 36% at 11:30 a.m., six minutes after the network became the first to project Biden’s victory. MSNBC’s viewership jumped 29% at 11:30 a.m. (NBC News had made its call at 11:25 a.m.) On Fox News, which made the call at 11:40 a.m., there was a 38% jump. Broadcast networks went into “special report” mode and also saw huge spikes, according to Nielsen.
In total, more than 21 million viewers across the six networks learned that Mr. Biden would be the 46th president, an unusually high total for a weekend morning.
CNN had, by far, the most viewership of any network, averaging about seven million between noon and 2 p.m. EST. MSNBC, the home network of many liberal viewers during the Trump years, averaged about 4.5 million. Fox News, which usually has a huge lead in viewership, had around three million viewers.
Fox News viewers also began to tune out a little faster than viewers of other cable networks, shortly after being greeted with sparkling graphics indicating that Mr. Biden was now president-elect. Viewers began leaving Fox News around noon, about 20 minutes after the network placed its call, according to Nielsen data.
By 3 p.m., as cable viewers began to tire of roundtable discussions of a Biden presidency, CNN had lost 24% of its midday audience and MSNBC 23%. But Fox News had lost 45% of its audience, to about 1.8 million viewers from about 3.4 million at noon.
The gap between Fox News and the other networks was even more pronounced Saturday night. More than 35 million people watched prime-time speeches by Mr. Biden and Vice President-elect Kamala Harris, according to Nielsen. CNN attracted the largest audience, with 13.6 million, and MSNBC had the second-highest total, 8.5 million. CBS led broadcast networks with 5.6 million.
But Fox News had the lowest viewership of any network that aired the speech: Only three million people watched.
No TV executive expected this trend to last more than a day or two. Fox News achieved record ratings throughout the year. It had the most prime-time viewership on election night of any network.
And indeed, on Monday it seemed that order had been restored. Fox News won on prime time as its hosts Tucker Carlson, Sean Hannity and Laura Ingraham — who continued to discuss the Trump campaign’s baseless claims of voter fraud and other alleged election irregularities — drew in averaged 3.8 million viewers, one million better than MSNBC and 1.3 million better. than CNN.