Despite below-zero temperatures for most of the past two weeks, this winter is shaping up to be a nonfactor for white-tailed deer.

And, while it’s true below-zero temps force deer to conserve energy, the lack of snow depth has made this winter’s first month a walk on the beach for deer across cold-country. As of this writing (Jan. 17, 2024), most of the Northern states have little to no snow cover. The lack of deep snow all but negates the bone-chilling temperatures.

For decades, biologists have used a simple formula to track and predict how weather will affect wintering whitetails. It’s called the Winter Severity Index, and it’s only applicable in far-northern regions. Central farmland and Midwestern states are not affected, because WSI numbers don’t hit critical marks but once or twice in a century.

Here’s how it works.

Winter Severity Index Formula for Deer

The formula consists of a simple counting exercise. For each day that you have an average snow depth of 18 inches or more, put down 1 point. Then, for each day that the low temperature is at or below 0 degrees (with the snow depth), put down 1 point. It’s important to note that average snow depth isn’t what you measure in your yard. It’s the average snow depth for your township or county. Also, the temperature is the low temperature not counting the wind-chill factor.

As of this writing, I know of no whitetail area that has amassed any points for the 2023-2024 winter. That’s not to say, however, that it won’t happen. Again, it’s a long winter. Right now, I’d be keeping an eye on the weather if you live and/or hunt deer in northeast Minnesota, northwest Wisconsin, northern North Dakota and Michigan’s U.P. There certainly will be reason for concern for our friends to the north (Ontario, Saskatchewan, et al), as snow depths are mounting up there and the bitter-cold temps are sure to follow.

Canada was hit exceptionally hard last winter. So hard, in fact, that many whitetail outfitters closed their doors for the 2023 season in hopes of rebuilding their local herds.

The lack of snow depth so far this year will also help deer, as it will hinder the hunting efforts of wolves. Areas with high wolf populations (Ontario, Minnesota, Wisconsin and Michigan’s U.P.) can see major deer losses when snow depths increase in late winter.

When deer do die from winter weather, there are typically many factors that lead to their losses. Click here to find out what eventually causes losses to the whitetail herd.