Dreaming of a white Christmas? Dream on

If you are dreaming of a White Christmas for this year, you’re probably going to be disappointed with temperatures forecast in the 50s for Putnam County and most of Indiana.

Nonetheless, here is some historical information on the occurrence of a White Christmas in the Indianapolis area, researched by the National Weather Service.

There are several ways to define a White Christmas, the weather service says. For the purposes of this historical look back, a White Christmas will be defined as any day that has either at least a trace of snow on the ground or experiences at least a trace of snow falling that day.

In more general terms, we’ll define a White Christmas as any Christmas Day that central Indiana sees snow.

So what is the chance of at least a trace of snow falling on Christmas Day?

Well, snowfall records on Christmas day have been kept in the Indianapolis area since 1871. And in that 148-year period of record, a trace of snow (or more) has fallen 67 times, which equates to a 45 percent chance of at least a trace of snow falling on Christmas Day.

The greatest Christmas Day snowfall was 5.9 inches in 1909.

The other possibility for a White Christmas would be if there were at least a trace of snow already on the ground. This could be old snow from a week ago, or just the day before.

As of Sunday night, there was still snow on the ground in Greencastle, but with 50-degree days in the immediate forecast with near 60 on Christmas, the ground cover may not last until Wednesday.

Snow depth records don’t go quite as far back, having been started in 1898. And in that 121-year span, at least a trace of snow has been reported on the ground on Christmas Day a total of 59 times. That equates to a 49 percent chance of at least a trace of snow on the ground on Christmas Day.

For a more robust snow covering, there has been one inch or greater of snow on the ground on Christmas Day a total of 34 times, which equates to a 28 percent chance to have this much snow on the ground on Dec. 25.

The greatest snow depth reported on Christmas Day was nine inches in 2004.

With both possibilities for a White Christmas explored, what then is our final chance? What would our probability be of having either a trace or more of snow falling, or a trace or more already on the ground?

Since 1871, this has happened in a total of 85 times, where either the snow has fallen or already been on the ground. This gives us an overall probability of 57 percent, meaning that nearly six out of every 10 years, on average, will see either some snow falling or some snow already on the ground for Christmas Day.

The last Christmas that saw snow on the ground in the Indianapolis area was in 2017.  The last time that snow fell on Christmas Day also occurred in 2017 when 0.1 of an inch fell. 

So if a White Christmas is your dream, then you’ll probably take heart in these numbers. Much more often than not, there will be at least a few flakes around to greet us come Christmas Day.

Central Indiana might have a shot at the warmest Christmas Day ever if you believe the forecast. The warmest ever reported was 64 degrees in 1893, while the coldest Christmas Day ever was -4 in 1983.