How February and This Winter Stacked Up in Illinois

Here are the time series plots of the statewide average temperature for February and winter (December-January-February) from 1895 to present (source: NOAA NCDC).

February

In the first plot, I have a red box around the temperature for 2014 and 2015. The only other time that we had a pair of extremely cold Februarys was 1978 and 1979. All the other cold Februarys were one-off events. According to NCDC, the statewide average temperature for February 2015 in Illinois was 19.5 degrees and the 9th coldest on record. Last February was nearly identical at 19.4 degrees.

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February – 7th Coldest on Record for Illinois

The statewide average temperature for February was 18.6 degrees. That is 12.3 degrees below the 1981-2010 average and the 7th coldest February on record. By comparison, February 2014 was 9th coldest at 19.5 degrees.

Here are some amazing statistics for Chicago. February was tied with 1875 for the coldest on record, according to the Chicago National Weather Service.  The average temperature for February was 14.6 degrees, 13.1 degrees below average. In addition, it was the 10th coldest month overall on record. February snowfall in Chicago was the third largest on record with 26.8 inches, 17.7 inches above average.

Snowfall for February in Illinois was widespread and well above average. Amounts of 15 to 20 inches were common in western and northern Illinois and 10 to 15 across central Illinois and parts of far southern Illinois. This was 8 to 12 inches above average in many locations. See maps below. Click to enlarge.

Some other February snowfall totals from around the state:

  • Chicago Midway AP: 28.3 inches
  • Rockford: 14.7 inches
  • Peoria: 12.8 inches
  • Quincy Lock and Dam: 11.2 inches
  • Springfield: 22.6 inches
  • Champaign-Urbana: 12.4 inches
  • Bloomington-Normal: 13.0 inches
  • Carbondale: 6.0 inches

The statewide average precipitation (rain plus the water content of snow) for February was 1.5 inches, 0.5 inches below average. Most of the state received 1 to 2 inches of precipitation, except for far southern Illinois which got 2 to 3 inches. See the second batch of maps for precipitation and precipitation departures from average.

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February – East Freezes While West Warms

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This map was created by the PRISM climate group out of Oregon State University. You can visit their homepage at http://prism.oregonstate.edu/

While Illinois and the eastern half of the US freezes, temperatures in California and the West are well above average this month. Here is the map of temperature departures from average for the first 25 days of February. This pattern of extremes was the theme of 2014, diminished in December and January, only to return in February 2015. The temperature pattern is a result of a persistent ridge of high pressure in the West and a trough of low pressure in the East. This is discussed in some detail over at climate.gov

Goldilocks’ Porridge: there is a tiny white strip on the map from Montana, through the Plains states, and into Texas, where temperatures are within a degree of average – not too hot, not too cold, but just right.

February On Track To Be Among The Coldest on Record for Illinois

image004February 2015 is on track to being one of the coldest February’s on record for Illinois. Data through February 24 puts the statewide average at 19.4° F. This is 11.5°F below average and slightly colder than last February’s 19.4°F. Before February, this was shaping up to be a mild winter with near to above-average temperatures (see graph to the left, click to enlarge).

At this point, February 2015 is ranked as the 8th coldest on record, edging out 2014 (see table below). The NWS forecasts show that temperatures for the rest of February will be 15 to 20 degrees below average. Therefore it is possible that it could move up the ranks. I will post more on this at the end of the month.

Ten Coldest February’s in  Illinois

  1. 1978 (16.9°)
  2. 1936 (17.2°)
  3. 1979 (17.4°)
  4. 1905 (17.6°)
  5. 1895 (17.7°)
  6. 1899 (18.0°)
  7. 1902 (19.2°)
  8. 2015 (19.4°) ** as of February 24
  9. 2014 (19.5°)
  10. 1914 (20.6°)

Statewide records go back to 1895.

February Snowfall in Illinois

Much of the southern third of Illinois received between 1 and 12 inches in this last winter storm. The highest amount reported was 12.5 inches at Smithland with several other stations reporting in the 7 to 8 inch range, including Jerseyville with 7.8 inches, Newton with 7.8 inches, and Brookport Dam with 8.8 inches.

map1The northern third of Illinois received a considerable amount of snow from the January 31 – February 2, 2015 storm.

As a result, total February snowfall has ranged from 15 to 20 inches in northeast Illinois and widespread amounts of 5 to 15 inches across the state (first map below). As a result for the month to date, most of the state is 1 to 8 inches above average except for the northeast which is 8 to 12 inches above average (second map below).

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Mild Winter Weather Not Expected to Last in Illinois

The mild winter weather is not expected to last in Illinois, but you probably already knew that.

How mild has December been? As of December 18, the statewide average temperature for December stands at 34.3 degrees, 2.1 degrees above average. Precipitation (both rain and the water content of snow) stands at 1.13 inches. Areas north of I-70 are much drier with amounts closer to half an inch, while south of I-70 amounts of 1-4 inches are common. At this point there has been very little snow in December, although that is about to change soon.

The latest NWS outlooks for January and the rest of winter are shown below (click to enlarge).

The temperature forecast for both January and the January-March period show almost all of Illinois with a higher chance of below-average temperatures. Only far northern Illinois escapes this forecast. On the other hand, precipitation has a higher chance of being below average across Illinois and the Great Lakes region. In most cases, these long-range forecasts only nudge the temperature by a few degrees. So, there is still little sign that this winter will be as severe as last.

The NWS does not issue a winter snowfall forecast. And, a combination of colder temperatures and less precipitation does not always translate into less snow. Many times colder weather produces lighter fluffy snow that accumulates but has less water content. We saw a lot of that last winter.  However, even if this forecast of colder and drier conditions captures the overall pattern of this winter, we could still see some significant winter storms. Be prepared.

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Champaign-Urbana Winter Weather Stats

Below is a summary of the February and winter weather statistics for Champaign-Urbana:

February

  • The average temperature for February was 19.0 degrees, which was 9.9 degrees below average and the 9th coldest on record.
  • The total snowfall for February was 14.6 inches, which was 8.8 inches above average and the 10th snowiest on record.

Winter

  • The average temperature for the three core winter months of December, January, and February, was 21.6 degrees, which was 8.6 degrees below average and the 9th coldest on average.
  • Our seasonal snowfall total that goes all the way back to November, was 41.1 inches as of March 3. That makes it the 7th snowiest seasonal total on record and 17.9 inches above the seasonal average of 23.2 inches.

It was certainly a cold and snowy winter but it was hard to beat those winters in the late 1970s and early 1980s. For example, the winter of 1977-78 experienced the most snow in Champaign-Urbana history with 67.2 inches. It was also the coldest during the December-February period at 20.2 degrees.

The official NWS cooperative observer site is located at the Illinois State Water Survey near the corner of First and Windsor in Champaign.