With little advance warning, all nets broke into regular coverage around 10 p.m. ET to cover the verdict in the George Zimmerman trial. Early Nielsen time-period averages show the four cable news networks combining for 10.6 million viewers — more than four times as many as were watching these channels one week earlier (2.4 million).
Fox News (3.68 million) and CNN (3.41 million) led the way, followed by HLN (2.21 million) and MSNBC (1.30 million). But in the key news demo of adults 25-54, CNN dominated with 1.72 million, followed by Fox News (1.11 million), HLN (980,000) and MSNBC (510,000).
From the 10.6 million in the 10 p.m. ET hour, viewership dropped off to 7.6 million tuning in for the 11 p.m. ET hour and 4.3 million by the midnight.
Nielsen is expected to produce more reliable program-based viewership totals for Saturday night later today or tomorrow, including a cume number that includes tune-in on the broadcast networks.
Two years ago, Casey Anthony’s acquittal drew a combined tune-in of 11.3 million on cable alone. (Nielsen limits its estimates to viewing done in homes, so this total does not include viewing done in offices, bars, airports or other places.)
For the first four days of last week, CNN, Fox News, HLN and MSNBC averaged a combined 4.01 million viewers in primetime — a 20% rise over the 3.35 million they drew for the Monday through Thursday of the week before the trial.
And in the key news demo of adults 25-54, the gain was a hefty 60% (1.075 million vs. 673,500) — an indication that interest in the case has brought a younger audience to cable news than it typically draws.
Fox News Channel remained the overall cable news ratings leader in primetime — drawing nearly as many viewers last week as CNN, HLN and MSNBC combined — but its four-day average (1.938 million) was actually down 3% from the 1.995 million it drew from June 17-20. The other nets were all up: CNN (729,300, up 70%), HLN (701,800, up 91%) and MSNBC (638,000, up 16%).
All four networks drew more adults 25-54 than the week before the trial. FNC led with 337,300 (up 18%), followed by HLN (306,300, up 151%) CNN (266,000, up 104%) and MSNBC (165,300, up 22%), who was deep in fourth place.
After placing second to FNC in 25-54 on the first three nights last week, HLN moved ahead on Thursday (362,000 vs. 339,000).
HLN was an especially big beneficiary during coverage of the Casey Anthony trial as well, drawing the biggest total audience in the network’s history. From 2:15 to 2:30 p.m. ET, when Anthony was found not guilty of murdering her young daughter, the network drew a big 5.2 million viewers — or about 18 times what HLN typically draws in the afternoon — to lead Fox News (2.9 million), CNN (2.3 million) and MSNBC (900,000), according to Nielsen.
In May, the verdict in the Arias murder trial drew a combined 6.9 million viewers on Fox News (2.76 million), HLN (2.2 million), CNN (1.52 million) and MSNBC (395,000).
The announcement of the verdict in O.J. Simpson’s trial in October 1995 was watched by more than 150 million viewers — a record audience for a single event — with about 75% of U.S. adults watching, according to Nielsen.