There are two precise times in the whitetail rut when the all-day sit, to me, is worth the time. The first is the few days before the primary peak of the rut. The second is about a week after the primary peak.
In both cases, the stand choice is the same: You want to be between sections of security cover that you either control enough to keep intentionally devoid of human activity all year or that are so thick and difficult to navigate that few people wander into them.
Ideally, your stand will be in dense enough cover that mature bucks will feel comfortable travelling through it in daylight, but it will also have a way in and out that allows you not to bump the bedding areas.
The particulars of finding bottlenecks that connect security cover depend on your region of the country, the terrain, the vegetation, the hunting pressure and other factors, but the principle is the same.
Now, back to the timing for the all-day sit.
The few days before the primary peak of the rut—in November in most of the U.S.—are predictable. For most of the northern and mid-latitude United States and Canada, the peak of the whitetail deer rut occurs in mid-November, typically centering around November 10-17. This timing is driven primarily by the photoperiod (shortening day length), which triggers estrus in does.
As the amount of sunlight dictates the timing, the peak is highly consistent from year to year in any given location. It is not meaningfully shifted by weather, moon phase or other factors—though, certainly, a very warm few days during this period can slow buck movement during the day.
Basically, in the Midwest and much of the northern and central U.S., peak breeding/chasing phase generally falls in early to mid-November. Bill Winke, the well-known bowhunting writer, would often point to November 7 as the likely peak in southern Iowa. In southern New York state, where I primarily hunt whitetails with a bow, November 12 has always been the day, or very near the day, when the chase phase gets wild.
So, you do need local, if anecdotal, information on the deer in your area to highlight the few days before the peak. I focus all-day sits on these days because the mature bucks are interested at this time, but they are not likely to be locked down somewhere with an estrous doe breeding her for 24-36 hours or so.
In most of the places we hunt, there just are not that many older bucks; therefore, when a lot of does are in estrus, those bucks are not likely to be cruising in daylight. You might catch them between does at any time during peak breeding, but the odds are not as high at that time.
The next best time to sit all day is after most of the does have been bred. The bigger bucks will now be desperately searching for that last estrous doe.
Exact local peaks can vary even within a state (especially farther south). The gestation period is about 200 days for whitetails, as peak breeding is timed for fawns to drop in late spring when conditions favor survival.
As a last tip, a Kansas outfitter once told me the best time to kill big bucks, on his properties, is actually in mid-December, when the youngest does (fawns from the previous spring) tend to come into estrus. As these does are less experienced, they often drag the bucks along as they follow their usual pattern. This can pull bucks into open fields near dark. Also, mature bucks that depleted much of their fat reserves cruising for does have a harder time resisting going to food sources in legal shooting light during very cold snaps.
