We are now in the doldrums of what broadcast TV considers the unimportant time. Sweeps are what matters! What are sweeps? I’m too lazy to explain it so here is a copy/paste from Wikipedia.

The American television measurement by Nielsen is based on three different methodological approaches. In the 25 TV markets with the highest sales (e.g. New York, Los Angeles, Chicago, Denver), the Local People Meter (LPM) is measured. Individuals register individually; the measurement is carried out on 365 days over 24 hours.[32] The SET Meter (Diary & Electronic) is used in 31 smaller markets (such as Nashville, Salt Lake City). In four sweeps in February, May, July, and November, target group data are collected with the diary and validated with the data of the devices (TV set on/off) in the participating households.[32] In the 154 TV markets with the lowest sales (e. g. Harrisburg, PA or Honolulu) the use of TV is only recorded using a diary survey.

Each year until 2018, Nielsen processed approximately two million paper diaries from households across the United States,[33][11] for November, February, May, and July—also known as the “sweeps” rating periods.[34] The term “sweeps” dates from 1954, when Nielsen collected diaries from households in the Eastern United States first; from there they would “sweep” west.[35][36] Seven-day diaries (or eight-day diaries in homes with DVRs) were mailed to homes to keep a tally of what was watched on each television set and by whom. Over the course of a sweeps period, diaries were mailed to a new panel of homes each week. At the end of the month, all of the viewing data from the individual weeks was aggregated. One exception to the normal sweeps periods occurred in 2008–09 when the February sweeps period was moved to March to accommodate the digital television transition, which was scheduled to take place on February 17, 2009. The transition date was later moved to June 12, but Nielsen kept the sweeps period in March that year rather than moving it again.

This local viewing information provides a basis for program scheduling and advertising decisions for local television stations, cable systems, and advertisers. Typically, the November, February, and May sweeps are considered more important; nevertheless, the July sweeps can have a local impact regarding personnel.[34]

In some mid-size markets, diaries provide viewer information for up to two additional “sweeps” months (October and January).

So, as you can see, January is not a Sweeps period in most markets, thus reruns.