There’s a new prime time in TV news: the afternoons.

The biggest draw on Fox News is not Tucker Carlson or Sean Hannity; it’s “The Five,” the 5 p.m. chat show that, except for live sports and the hit drama “Yellowstone,” was last year’s most-watched program on all of cable TV.

In January, Ari Melber’s 6 p.m. legal affairs program outranked everything else on MSNBC — the first time in the network’s 27 years that a show outside the prime-time window of 8 to 11 p.m. took top honors. On CNN, Erin Burnett at 7 p.m. and Jake Tapper at 4 p.m. drew bigger audiences than the once-peerless evening lineup.

Since their inception in the mid-1990s, 24-hour cable networks have fixated on the cult of prime time, when megawatt personalities like Keith Olbermann, Megyn Kelly and Rachel Maddow minted loyal fans. Anchors’ careers peaked when they landed a show at these most watched and most lucrative hours of the day.

Now, like almost everything else in the TV news business, that’s changing. Instead of flipping on CNN at 8 p.m. for the latest on the presidency or the pandemic, viewers are dipping in before dinner and then drifting away. Mr. Melber and Nicolle Wallace, who hosts a 4 p.m. show, expanded their audiences in the past year, even as ratings for most prime-time news shows declined or stagnated.

The reasons are myriad. Without the visceral urgency of a dangerous virus — or a sitting president who tweets erratically late into the night — America’s news obsessives may simply feel more comfortable changing the channel in the evenings rather than waiting on tenterhooks for the latest development. At the same time, prime-time stars like Ms. Maddow have moved on from their regular time slots.

“The biggest show on earth, the Trump administration, is over for now,” said Mosheh Oinounou, a former “CBS Evening News” executive producer. “It’s no different from traditional TV — the plot is less interesting, and some of the characters have left the show.”

Cable news is also facing its toughest competitor yet: streaming.

Americans over 65 are the core audience of 24/7 news channels, but these older viewers are increasingly turning to streaming platforms like Netflix or Amazon Prime for their entertainment. According to Nielsen, Americans over 65 watched nearly twice as many hours of streaming television in December 2022 as they did in December 2020 — the biggest increase among any age demographic in that period.

“Unless there’s something supercompelling going on in the world, prime-time viewers have so many other streaming options now to watch,” said Jonathan Klein, a former president of CNN and a co-founder of Hang, a streaming sports platform. “There’s so much more choice than there used to be. You can watch ‘Top Gun: Maverick’ on streaming. It’s hard for the news to compete with Maverick.”

For network executives, the trends have scrambled a few longstanding assumptions.

For one thing, prime-time hosts don’t necessarily have to be the omnipresent cultural figures they once were — and salaries can be adjusted downward accordingly. And the evening does not necessarily have to be reserved for reviewing the day’s news. Producers can experiment with documentaries and other nonfiction programming that may draw bigger audiences.

Typically, prime-time viewers tune in by appointment, expecting to see a familiar face discuss the news of the day. But CNN said last month that it would fill its empty 9 p.m. slot with a mélange of one-off specials and occasional cameos by unorthodox hosts like the former basketball star Charles Barkley.

The network’s new president, Chris Licht, has presented this strategy as bringing “fresh and unique perspectives to the news,” but it’s also a recognition that the appetite for current events in the evenings has waned.

CNN’s 9 p.m. audiences fell after Chris Cuomo, once the network’s highest-rated anchor, was fired in 2021. Last fall, Mr. Licht tried reviving the 9 p.m. slot by moving Mr. Tapper from 4 p.m. After just six weeks, and dismal ratings, Mr. Tapper returned to the afternoons, where his show, “The Lead,” now regularly attracts more viewers than CNN’s evening programs.

At MSNBC, the long-running 9 p.m. program “The Rachel Maddow Show” was so popular in the Trump years that it briefly lifted MSNBC’s prime-time viewership above that of Fox News — the cable news ratings king — in the key 25-to-54 age demographic.

But MSNBC agreed last year that Ms. Maddow could reduce her hosting duties to just once a week, on Mondays. Her replacement from Tuesday to Friday, the political analyst Alex Wagner, has struggled to build an audience. Her ratings in 2023 are tracking about 30 percent lower than what Ms. Maddow drew in the first quarter of last year.

Ratings in January may have been affected by the breaking stories that played out during daytime hours, including the battle for the House speakership, the Alex Murdaugh murder trial and the drama over a Chinese spy balloon. Still, in February, Mr. Melber and Mr. Tapper remained virtually tied for the top-rated shows on their networks, a sign of staying power.

These trends are playing out amid a broader drop in overall viewership in cable news. In 2022, MSNBC’s prime-time audience declined 21 percent from a year prior, and CNN lost 33 percent.

Fox News is an exception; its prime-time viewership fell just 2 percent from 2021 to 2022. And its afternoon showcase, “The Five,” is a particular standout.

Fueled by chummy exchanges among co-hosts like Jesse Watters and Greg Gutfeld, “The Five” leaped past Mr. Carlson last year to achieve Fox News’s biggest average audience, a major shift at a network where prime time was always king. (Mr. Carlson still outranks “The Five” among adults under 50, the key demographic for advertisers.)

Even the family that controls Fox is aware that casual observers may not be fully aware of the afternoon show’s success. “People will be surprised, but the No. 1 news show in America is ‘The Five,’” Lachlan Murdoch, chief executive of the Fox Corporation, said at an investor conference last week. “It’s a great, energetic show, a panel show that has opinions from all sides of politics.”

“The Five” has also incubated two of the network’s rising stars. Fox News turned to Mr. Gutfeld to lead a new 11 p.m. comedy show that has turned into a major hit. The show far outranks its strait-laced, news-focused competitors on CNN and MSNBC and routinely pulls in more viewers than comedy stalwarts like Jimmy Kimmel and Jimmy Fallon.

“The Five” isn’t the only afternoon show on Fox News that has been doing well relative to its in-house competition. In February, Mr. Watters’s 7 p.m. show drew more viewers than Mr. Hannity at 9 and Laura Ingraham at 10. Bret Baier’s “Special Report,” at 6 p.m., also attracted a bigger viewership than Ms. Ingraham.

In some ways, the shift back to afternoons and early evenings is a throwback to the traditional dinnertime network newscasts that, for generations, summarized current events for a mass audience at 6:30 p.m.

Today, the 6:30 newscasts on ABC, CBS and NBC still rank among the highest-rated programs on all of broadcast and cable TV. ABC’s “World News Tonight,” anchored by David Muir, was the most-watched nonsports program on all of television in 31 of 52 weeks last year.

Mr. Oinounou, the former CBS producer who now runs Mo News, an independent outlet distributed on Instagram and other digital platforms, noted that a combined audience of roughly 20 million people still watched those traditional newscasts. He said cable news was simply catching up to an old trend.

“This is what we’ve been seeing for years,” Mr. Oinounou said, laughing. “People look for a digest of news as they’re about to eat dinner, and then we’ll send you to more traditional entertainment — written by TV writers as opposed to politicians in Washington.”