white Christmas – Illinois State Climatologist

December 14, 2015

Chance of a White Christmas in Illinois

I just heard “Let It Snow” on the radio and it reminded me that it’s time to do the annual post on …

What are the historical chances of a White Christmas?

We define a “white Christmas” as having at least an inch of snow on the ground on December 25. The map below shows the odds across the state. It should come as no surprise that the highest odds are in northern Illinois. In general, the odds are about 40-60 percent in the northern third of Illinois, 20-40 percent in central Illinois, and 0-20 percent in southern Illinois.

There can be large differences between nearby sites. Snowfall is notoriously difficult to measure with blowing, drifting, and melting. Two nearby sites may have different results due to exposure to the sun and the wind as well as the dedication of the observer to report on Christmas Day.

WC_Chance_8110

What happened last year?

We had just a little bit of snow on the ground in parts of the northern half of Illinois on December 25, 2014 – hardly impressive. dec25-2014

What is the most snow on Christmas Day?

Here are the largest snow depths on Christmas Day (12/25) for selected locations around the state:

Chicago, 17 inches in 1951
Rockford, 14 inches in 1951 and 2000
Quad Cities, 12 inches in 1909
Peoria, 10 inches in 1909
Springfield, 10 inches in 1915
Champaign-Urbana, 9 inches in 1983
Carbondale, 9 inches in 2004

What are the odds this year?

What are the odds this year? They may be a little better than you think. While December has been incredibly mild so far, 10 degrees above average, that could change for short periods of time. Keep an eye out for developing storms as we get into Christmas week.

[An earlier version of this post had an interesting run from the GFS model showing a potential for snow around Christmas, but subsequent model runs did not support this. ]

December 12, 2014

Chance of a White Christmas

I just heard Bing Crosby on the radio and it reminded me that it’s time to do the annual post on …

What are the historical chances of a White Christmas (defined as at least an inch of snow on the ground on Christmas Day)? The first map below the shows the odds across the state. It should come as no surprise that the highest odds are in northern Illinois. In general, the odds are about 40-60 percent in the northern third of Illinois, 20-40 percent in central Illinois, and 0-20 percent in southern Illinois.

There can be large differences between nearby sites. Snowfall is notoriously difficult to measure with the potential for two nearby sites having different results due to exposure to the sun and the wind.

After a cold November, December has been much milder this year. The latest NWS 8-14 day forecast includes December 25 and continues to show Illinois with a good chance of warmer-than-average temperatures. And today there is not much snow in Illinois (map below). Stay tuned to your local forecast as we get closer. Continue reading “Chance of a White Christmas”

December 13, 2012

Chances of a White Christmas

What are the chances of a White Christmas (defined as at least an inch of snow on the ground on Christmas Day)? The National Climatic Data Center has updated their US map to show the current 1981-2010 averaging period. The odds are high in the Rocky Mountains, the upper Midwest, and the Northeast. However, a White Christmas is rarely, if ever, seen in much of the southern half of the US or along the West Coast.
We did a similar map with more detail for Illinois last year (second map). It should come as no surprise that the highest odds are in northern Illinois. In general, the odds are about 40-60 percent in the northern third of Illinois, 20-40 percent in central Illinois, and 0-20 percent in southern Illinois.
There can be large differences from site to site. Snowfall is notoriously difficult to measures with two nearby sites having different results due to exposure to sun and wind.

December 16, 2011

Odds of a White Christmas in Illinois

We just updated the odds of a white Christmas in Illinois, based on 1981-2010 data. We created the map using stations that had at least 20 years of snowfall data during the 1981-2010 period. A year with a white Christmas was defined as having measurable snow on the ground on December 25.
There can be large differences from site to site. Snowfall is notoriously difficult to measures with two nearby sites having different results due to exposure to sun and wind. In general, the odds are about 40-50 percent in the northern third of Illinois, 20-40 percent in central Illinois, and 0-20 percent in southern Illinois.