Warmer weather and the first full week of daylight saving time may have sapped the ratings of numerous shows, but that didn’t keep auds from exhibiting a zeal for zombies on Sunday.

AMC’s second-season finale of “The Walking Dead” set basic cable records in the 18-49 demo and was the week’s No. 1 scripted program in the category. It trailed only music contests “American Idol” and “The Voice.”

But pretty much everywhere else you looked, especially early in the week, ratings suffered as Americans enjoyed the extra hour of sunlight and didn’t turn on their televisions until later in the evening. From Monday through Wednesday, when it was especially nice outside in the Northeast and Midwest, Nielsen estimates that the percentage of homes watching TV in the 8 o’clock hour declined by a significant 11% vs. the previous four-week average — a noticeably bigger drop than a year ago.

Viewing levels weren’t off quite as much in the 9 o’clock hour, but the dropoff contributed to season lows for a lot of shows, including “Modern Family,” “Criminal Minds” and “New Girl.”

Among other lowlights in the frame for the broadcasters: NBC drew less than 3 million viewers on Wednesday; no broadcaster could top TBS’ repeats of “The Big Bang Theory” in 18-49 on Tuesday; and CW’s “Hart of Dixie” (albeit with a repeat) did a 0 share in several categories on Monday.

Overall for the week of March 12-18, CBS and Fox tied for the lead among adults 18-49 with a 2.2 rating/6 share, followed by ABC (2.0/6), NBC (1.6/5), Univision (1.5/4) and top cabler TBS (0.9/3). CBS edged out Fox in adults 25-54 (2.8/7 to 2.7/7) and won easily in total viewers (8.1 million to 6.8 million for runner-up ABC).

For CBS, which aired repeats of its Monday and Tuesday hits, the start of the NCAA men’s basketball tournament was a give-and-take: Thursday’s primetime 18-49 average (1.7) was well below what the net does with originals on the night, but Friday (2.3) and Saturday (2.2) were well above average and easily won the nights.

Repeats of “NCIS” (2.1/7, 12.98m) and “NCIS: Los Angeles” (1.9/5, 11.33m) were competitive in demos and drew more total viewers than any program other than “American Idol” and “The Voice.”

Fox claimed the week’s No. 1 program in 18-49 and total viewers with Wednesday’s two-hour “American Idol” (5.4/16 in 18-49, 18.38m), while Thursday’s results show placed fourth in the demo rankings (4.6/14, 16.02m).

A repeat of Kiefer Sutherland drama “Touch” got some good sampling behind “Idol” on Thursday (2.2/6, 8.57m).

ABC was led by “Modern Family” (4.5/12, 10.60m), fifth for the week in 18-49 but expected to vault to No. 1 in full-week numbers based on its impressive DVR playback trends (Daily Variety, March 20).

The net was also stronger than usual on Monday with the two-hour finale of “The Bachelor” (2.9/8, 9.23m) and post-show “After the Final Rose” (3.3/8, 9.87m).

Thursday saw a fairly good bow for Ashley Judd drama “Missing” (2.1/6, 10.60m), which ran second for its 8 o’clock hour in 25-54 and total viewers. And on Sunday, “GCB” dropped off some in its third week (2.0/5, 6.07m).

NBC was paced by “The Voice” (5.2/14, 14.51m), the No. 2 show of the week in 18-49, though it was on the low side and dipped behind Fox’s “Idol” as the top show of the week. It and Monday lead-out “Smash” (2.4/6, 7.04m) have helped the net post year-over-year gains for eight straight weeks.

Best news for the Peacock was the return of Thursday comedy “Community” (2.2/7, 4.75m), which took advantage of “Big Bang Theory’s” absence to hit a 14-month high. It fared especially well among men 18-34 (3.2/12), placing among the top five primetime shows for the week.

Not so hot was the debut of reality show “Fashion Star” on Tuesday (1.6/4, 4.55m), though it’s too early to count it out since it will be getting a “Voice” lead-in in a couple of weeks.

On the cable side, “The Walking Dead” (4.7/11, 8.99m) was television’s No. 3 program for the week in 18-49 and No. 1 in men 18-34 (5.7/17). And the post-show episode of “Talking Dead” landed among the week’s top 25 shows as well (2.3/6, 4.30m).

MTV’s season finale of “Jersey Shore” (2.7/8, 4.99m), though down from recent years, still packed enough of a punch to win its Thursday hour in 18-49.

Another standout among young viewers was Comedy Central’s “South Park” (1.5/4 in 18-49, 2.63m), which won its Wednesday slot in adults 18-34 (2.1/7) and was the night’s No. 1 show in men 18-34 (3.3/12).