Winter 1997-98 in Wisconsin

    Winter 1997-98 (December through February) was the warmest in Wisconsin since modern record keeping began in 1895 and quite possibly the warmest since statehood in 1848.  The warm temperatures were associated with El Niño, a climatological condition which links sea surface temperatures in the tropical Pacific Ocean to circulation and precipitation patterns around the world.

    The statewide mean temperature of 26.2°F shattered the previous record set during the 1930-31 season by 2.4°F, and was nearly 10°F degrees above the 30-year normal.  There is considerable evidence that the winter of 1877-78 (also an El Niño year) was comparably mild, but the lack of statewide records makes direct comparison difficult.  Temperature departures were highest in northwestern Wisconsin and least in east central and southeastern sections.  Precipitation totals averaged near to somewhat above normal.

    Minimum (nighttime) temperatures exhibited higher departures than daily high temperatures. Nighttime temperatures ranged from about 10°F above normal in southeastern Wisconsin to more than 14°F above normal in the northwest.  In contrast, daily highs averaged between 4°F and 8°F above normal and, in fact, relatively few daily maximum records were set during this winter season.  For example, only one daily maximum temperature record fell at Madison, on February 26.  The small number of minimum temperatures dropping to zero or below is indicative of the warm nighttime temperatures.  Madison also set early ice-out records for three area lakes: Mendota, Monona, and Wingra and record short ice durations in the case of Lakes Mendota and Monona.

 
 
Climate 
Division
Mean 
Temp. 
(°F)
  
Normal 
Temp.
Depart. 
From 
Normal
Total 
Precip. 
(in.)
  
Normal 
Precip.
Depart. 
From 
Normal
Percent 
of 
Normal
Northwest 
24.2
13.1
11.1
3.30
3.15
0.14
105
N. Central
23.3
13.2
10.1
3.47
3.32
0.15
105
Northeast
24.6
15.8
8.8
4.66
3.78
0.89
124
W. Central
26.2
16.3
10.0
4.35
2.97
1.38
147
Central
26.8
17.6
9.1
4.17
3.46
0.71
120
E. Central
27.6
19.7
7.9
4.58
3.91
0.66
117
Southwest
28.2
19.2
9.0
4.74
3.43
1.32
138
S. Central
29.2
20.3
8.9
4.66
3.91
0.74
119
Southeast
30.3
21.8
8.5
5.48
4.46
1.02
123
 
(Note: Total precipitation is rain or water equivalent of snowfall)

 
Year
Temp
Rank
1997-98*
26.2
1
1930-31*
23.8
2
1982-83*
23.7
3
1986-87*
23.4
4 (tied)
1931-32
23.4
4 (tied)
 
(Note:  Asterisk * denotes El Niño seasons.)

 
Lake
New Record Early Opening
Previous 
Record
Shortest Ice Duration
Previous 
Record
Mendota
February 27 1998
March 8, 1983
47 days 
(1997-98)
54 days 
(1982-83)
Monona
February 27 1998
March 6, 1983
49 days 
(1997-98)
56 days 
(1982-83)
Wingra
February 26 1998
March 2, 1882
70 days 
(1877-78)
-

Milwaukee: 1997-98 average temperature was 30.6°F (8.5°F above normal), 5th warmest on record, (1931-32 ranks first with a mean temperature of 32.6°F).

Madison: 1997-98 average temperature was 28.4°F (9.0°F above normal), ties for 4th warmest with 1889-90, (1877-78 ranks first with a mean temperature of 31.8°F).

Green Bay: 1997-98 average temperature was 27.1°F (9.5°F above normal), 3rd warmest on record (1953-54 ranks first with a mean temperature of 28.7).

La Crosse: 1997-98 average temperature was 28.8°F (10.6°F above normal), 3rd warmest on record (1877-78 ranks first with a mean temperature of 34.7°F).
 
 
 
 

MADISON
 
Zero/Sub-zero Days
Year
2
1997-8
4
1952-3
5
1907-8, 1991-92
6
1930-1, 1931-2
7
1918-9, 1986-7

 

MILWAUKEE
 
Zero/Sub-zero Days
Year
1
1982-3, 1997-8
2
1905-6, 1920-1, 1952-3
3
1910-1, 1930-1, 1986-7, 1996-7
4
1907-8, 1918-9, 1937-8, 1938-9, 1953-4, 1991-2, 1992-3, 1994-5
5
1908-9, 1931-2, 1955-6, 1959-60, 1988-9

 

LA CROSSE
 
Zero/Sub-zero Days
Year
2
1997-8
5
1942-3
6
1907-8
7
1920-1, 1930-1
9
1982-3, 1986-7

 

GREEN BAY
 
Zero/Sub-zero Days
Year
5
1920-1
6
1930-1, 1931-2, 1997-8
7
1918-9, 1986-7
8
1907-8, 1982-3
9
1908-9, 1943-4

 

OSHKOSH
 
Zero/Sub-zero Days
Year
4
1982-3, 1997-8
5
1900-1
6
1991-2
8
1920-1, 1930-1, 1986-7
9
1918-9, 1931-2

 

SUPERIOR
 
Zero/Sub-zero Days
Year
8
1997-8
16
1986-7
18
1930-1, 1939-40, 1941-2
23
1920-1, 1982-3, 1991-2
24
1918-9
26
1943-4

 

EAU CLAIRE
 
Zero/Sub-zero Days
Year
4
1930-1
5
1997-8
11
1920-1
13
1907-8
14
1986-7