Chance of a Repeat of Last Winter

Probably the most frequently asked question I get these days is “Will this winter be as bad as last winter?” I discussed this a bit in an earlier post. The National Weather Service forecast does not show a repeat of last winter based in part on winter trends and the possible arrival of El Niño.

Another way to look at this is through the historical data. I looked at the 20 coldest winters for Illinois since 1895 and what the next winter was like (table below). “Temp” is short for temperature and “depart” is short for temperature departure from average.

Since this last winter was #9, that leaves us with 19 other winters where we can look at the next year. Of those 10 of the following winters were below average. In fact, we see the three-peat winters of 1976-77, 1977-78, and 1978-79 in the line up as well as the repeat winters of 1903-04, and 1904-05.

Or if you are an optimist, 9 of the following winters were at or above average. If you look at the plot below the table, you can see that with the exception of the late 1970s and the early 1900 episodes, our colder winters have been followed by a winter more moderate – maybe not warm but at least not as cold. Also we have seen a warming trend of about 1ºF in the historical record. For the record, I’m hoping for a milder winter.

Top 20 coldest winters (December-February) and the following winters.
Rank Winter Depart Next Winter Depart
1 1977-78 -9.5 1978-79 -9.3
2 1978-79 -9.3 1979-80 -1.4
3 1935-36 -9.0 1936-37 +0.1
4 1917-18 -8.8 1918-19 +3.7
5 1976-77 -8.3 1977-78 -9.5
6 1903-04 -7.9 1904-05 -7.4
7 1962-63 -7.6 1963-64 -3.2
8 1904-05 -7.6 1905-06 +0.4
9 2013-14 -7.4 2014-15   ??
10 1911-12 -6.3 1912-13   0
11 1981-82 -6.2 1982-83 +4.6
12 1898-99 -6.1 1899-00 -2.5
13 1901-02 -6.0 1902-03 -2.9
14 1909-10 -5.7 1910-11 +0.1
15 1919-20 -5.3 1920-21 +3.9
16 1969-70 -4.7 1970-71 -1.3
17 1958-59 -4.4 1959-60 +1.0
18 1928-29 -4.3 1929-30 -0.1
19 2000-01 -4.3 2001-02 +5.6
20 1983-84 -3.9 1984-85 -2.9
Statewide average winter temperature for Illinois. Source: National Climatic Data Center.
Statewide average winter temperature for Illinois. Source: National Climatic Data Center.
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