Near Normal Temperatures

Annual averaged temperatures in the Midwest were near normal (Figure 1). The entire region was within 2°F of normal when averaged over the entire year. There were however periods of both warm and cold that offset each other. April was the 2nd coolest on record (1895-2018) while May set the record as warmest for the region. Other months were quite warm (June ranked 13th warmest and September ranked 15th warmest) or cool (November ranked 11th coolest) as well. There were notable swings in temperature across the region in 2018. Spring saw a sudden jump from cold in April to warm in May and fall had a similar sudden transition from warmth in September and the first 10 days of October to cold in the rest of October and November. There were also big swings of temperature in January, July, and December in 2018. Statewide temperatures set records in three months. April had new record cold in Iowa and Wisconsin. May had record warmth in Illinois, Indiana, Kentucky, Missouri, and Ohio. Ohio set another record for warmth in September. There were numerous other top-10 rankings for states including top-10 warmth in February (Kentucky and Ohio), May (all nine Midwest states), June (Iowa and Missouri), August (Michigan), and September (Illinois, Indiana, Kentucky, and Ohio). Top-10 statewide rankings on the cool side occurred in April (all nine Midwest states) and November (Illinois and Missouri).

Record Breaking Precipitation

Precipitation was record breaking on the wet side in 2018 (Figure 2). The Midwest as a whole was just wetter than 1993 (using preliminary data for December) with an average of 42.88 inches across the region. Statewide totals ranked among the wettest in their histories (1895-2018) with Iowa, Kentucky and Wisconsin ranking 2nd wettest, Ohio 3rd, Indiana 5th, Michigan 11th, and Minnesota 17th. Only Missouri had below-normal annual precipitation falling 0.27 inches short of normal. Statewide values ranked among the wettest in several months including February, June, August, September, October, and November. Missouri also had a top-10 driest month in April. More than 120 stations in the region set new annual precipitation records (minimum of 30 years period of record) with dozens of those stations having periods of record exceeding 100 years. Some of the bigger cities that set such records in 2018 were Louisville and Lexington in Kentucky, Columbus in Ohio, Waterloo in Iowa, and Green Bay in Wisconsin. Each of these cities had period of record of at least 124 years.

Less than 10 Percent of Midwest in Drought

Drought in the Midwest began 2018 with just under 10 percent of the region in drought (Figure 3). In the summer drought expanded and intensified, particularly in Missouri and southern Iowa but also in Michigan, peaking in mid-August before being completely eradicated by the end of 2018. At its peak in August, nearly 20 percent of the region was in drought, with more than 8 percent in severe drought and 0.77 percent in exceptional drought (the highest category) (Figure 4). More than 43 percent of the region was classified in drought or abnormally dry in mid-August but by the end of the year there was no drought and less than 1 percent of the region was classified as abnormally dry which was the lowest percentage since May of 2018.

Problematic Flooding

Flooding was a problem in the region for a good part of 2018. Flooding started in February and continued to pop up as a problem throughout the year as heavy rains fell, particularly in two large areas: northern Iowa to southern Wisconsin and into neighboring areas and also in the Ohio River Valley. During the year, at least 14 fatalities were attributed to flooding or flash flooding in the Midwest. Property damages were estimated at more than $300 million through September with data for the last three months still pending. Crop damages in Iowa and Wisconsin alone topped $17 million.

Severe Weather Events

Severe weather in the Midwest was not typical with very little in April, near the climatological peak, and yet with tornadoes in both January and December. The December 1st tornado outbreak in Illinois set a new state record with 28 tornadoes (Figure 5). There were about 500 homes damaged and 22 injuries in the EF-3 tornado that struck Taylorville, Illinois on the 1st. There was also a deadly tornado near Aurora, Missouri the previous day. Another significant severe weather event was the sinking of a duck boat in the Ozarks of Missouri on July 19th (Figure 6). The duck boat was being used to give a tour on the lake when a severe thunderstorm whipped up large waves and sank the boat.

Agricultural Impact

Spring planting, especially in the northern half of the region, was delayed due to wet and cold conditions in March and then cold and snowy conditions in April. Wet fields in the fall also affected harvest in many areas with fields too wet, and in some cases with standing water, to allow tractors into the fields.

Snow Events

Winter weather struck in April in the north bringing records snows to Iowa, Minnesota, and Wisconsin. The storm had snow totals of more than 2 feet in many locations. Green Bay, Wisconsin set a record for its snowiest April on record 36.7 inches which also ranked as the 2nd snowiest month all-time (December 2008). A blizzard hit on the Thanksgiving weekend in late November snarling air and ground traffic from Kansas City to Chicago.