(Radio Iowa) – To some Iowans, it just isn’t the holiday season if there isn’t snow on the ground. If a white Christmas is on your wish list, you’ll have the best shot of finding flakes across Iowa’s northern-most counties. National Weather Service meteorologist Brad Small says they’ve studied the data spanning back decades and have compiled a map showing the probabilities of having snow on the ground on December 25th.

“Iowa can probably be generally weighted into four different tiers actually, with about a 60-plus-percent chance toward the Minnesota border, and then it steps down, Highway 20 corridor 50-percent, then 40, and then it gets down into the 30s as you get closer to the Missouri border,” Small says. “So it kind of behaves as you’d expect, with better chances the farther north you go.”

National Weather Service graphic

Since Christmas is still 19 days away, Small says it’s difficult to predict whether we’ll have a significant snowfall in Iowa by then. “It’s a little too far out to put too much on the end of the month,” Small says. “Probably the historical probabilities work better than anything else, at this point. There are some snow chances this weekend. Confidence in where that occurs and how much is pretty low, and it doesn’t look like to be a major system, so it’s potential, even if we do get snow this weekend, it could melt before Christmas.”