The first image is a chart of average chances from 1981-2010. (Click here for a larger version.) A “White Christmas” here is defined as an inch or more on the ground the morning of December 25.
Now here’s what was actually on the ground, December 25, 2014:
Less than average. Only 35.5% of the country covered in snow. Most of the USA had colder (relative to average) weather for Thanksgiving.
Last year? Indy had a trace of snow, but no White Christmas. There was 41.7% of the country covered by snow on December 25, 2013:
It was even snowier December 25, 2012, with 51.1% of the country reporting snow. Indy had a trace, but no White Christmas. We missed it by a day. Seven inches of snow fell December 26.
Our last Indy White Christmas? It was 2010, with five inches of snow on the ground, and a half-inch falling on the big day itself.