The Dry April That Wasn’t

April ended colder and wetter than average across the state. The preliminary statewide average April temperature was 49.2 degrees, 3.4 degrees below the 30-year normal and tied for the 27th coldest on record going back to 1895. The preliminary statewide average total April precipitation was 4.36 inches, 0.58 inches above than the 30-year normal and the 43rd wettest on record.

Data are provisional and may change slightly over time

April Temperature Rollercoaster

Warm weather spilled over from March into the beginning of April. Average temperatures between April 1 and April 10 ranged from 1 to 6 degrees above the 30-year normal across the state. A strong cold front moved through the region between April 9 and 11, with following unseasonably cold air that quickly decreased temperatures. Average temperatures between April 11 and 20 ranged from 5 to 15 degrees below normal (see maps below).

Many stations across the state recorded daily maximum temperatures in the mid- to high 80s during the first 10 days of April, only to record daily minimum temperatures in the mid- to low 20s in the second 10 days. For example, stations in McHenry and Woodford Counties recorded high temperatures of 82 degrees on April 9 and one week later recorded low temperatures of 20 degrees on April 16. Fourteen stations around the state broke daily April high maximum temperature records and three stations broke daily April high minimum temperature records between April 7 and 12. Subsequently, 20 stations broke the daily April low maximum temperature records and 30 stations broke the April low minimum temperature records between April 13 and 20.

The plots below show daily maximum and minimum temperatures, as well as daily average temperature departures from normal, for April in Jacksonville. The average temperature in Jacksonville on April 8 was nearly 20 degrees above the long-term average, and the average temperature 10 days later on April 18 was nearly 20 degrees below the long-term average.

Overall, April average temperatures ranged from the low 30s in northern Illinois to the mid-50s in southern Illinois. April was cooler than normal across the state. The preliminary statewide average April temperature was 49.2 degrees, 3.4 degrees cooler than normal and the 27th coldest on record back to 1895. April ended the consecutive four-month streak of warmer than normal months going back to December 2019.

Spring Freeze

As a result of the strong cold front that moved through the region in mid-April, minimum temperatures dipped below freezing as far south as Pope County. Stations in northwest Illinois recorded minimum temperatures in the teens on April 8. Late-season freeze events in early to mid-April are not uncommon; however, last month’s event followed a prolonged period of well above average temperatures. The plot below shows daily average temperature departures from the 30-year normal from March and April in Carbondale. Between March 1 and April 12, Carbondale experienced twice as many warmer than normal days than cooler than normal days. Furthermore, the minimum temperature in Carbondale last dipped below freezing on March 7 before reaching 30 degrees on April 14.

Flowering trees, shrubs, and tender perennials broke dormancy and began to green in response to prolonged warm conditions throughout March and early April. This increased the vulnerability of Illinois specialty crops such as peaches, strawberries, and asparagus to the late-season freeze. University of Illinois Extension reported some damage to specialty crops in most regions of the state as a result of the freeze event in mid-April. The extent of damage was likely curtailed by successful warming of the sub-freezing temperatures five to seven days prior to the event.

Heavy Late-April Rain

The first two-thirds of last month was somewhat to very dry across the state, with most areas experiencing less than 50 percent of normal precipitation by April 20 (see maps below). The station in Rosiclaire in Hardin County recorded less than one-half an inch of rainfall in the first 22 days in April, putting last month on track for one of the driest Aprils on record. Likewise, areas of east-central Illinois were experiencing a 2-inch precipitation deficit by April 22. The prolonged dry conditions caused soils to dry considerably. Both 4-inch and 8-inch soils at the Illinois Climate Network station in Bondville in Champaign County were at their driest April levels since 2012. The dryness was quite a contrast to April 2019 and was beneficial for farmers to make planting progress.

The dry weather was brought to an abrupt end by a series of storms that tracked across Illinois over the last week in April, generating very heavy rainfall and widespread 2- to 4-inch accumulations along the Interstate 55 corridor between the St. Louis Metro East and Chicagoland (see map below). The heaviest rainfall was in central Illinois between Mason and McLean Counties.

The Bloomington Waterworks station recorded 4.99 inches on April 26, which was the largest single-day April precipitation event on record at that station going back to 1949. The wettest point in the state last month was Havana in Mason County. The Havana station recorded just over 2 inches of precipitation in the first 22 days of April and was experiencing nearly a three-quarter-inch precipitation deficit at that time. Havana received nearly 6 inches of precipitation in the following seven days and ended the month with an all-time April record-breaking precipitation total of 7.8 inches (see plot below).

Heavy precipitation in late April caused flash flooding across central and northeastern Illinois as well as inundated fields and resultant planting delays. Additionally, many gauges along the Illinois River, Des Plaines River, and Mississippi River south of Hardin were pushed into the flood stage.

Total March precipitation ranged from just under 8 inches in central Illinois to less than 2 inches in southeastern and northwestern Illinois. These totals ranged from over 175 percent of average April precipitation in central to less than 50 percent of average April precipitation in southern Illinois.

Overall, the preliminary statewide average April precipitation was 4.36 inches, 0.58 inches above than the 30-year normal and the 43rd wettest on record. The April average does not reflect the 5- to 6-inch differences in precipitation between central and northern/southern Illinois.

Most of the northern half of the state experienced measurable snowfall last month. April totals ranged from over 8 inches in north central Illinois to just over one-tenth of an inch along Interstate 72. A single storm in mid-April produced widespread 24-hour snowfall totals between 1 and 3 inches in central and northern Illinois, with a few much larger isolated totals. Areas of Warren, Henry, Knox, and Mercer Counties received more than 6 inches of snowfall in a single day, including the third and fifth highest single day April snowfall totals in Kewanee and Galesburg, respectively. This event was also the latest 5-inch or larger snowfall event on record at nearly a dozen stations around the state.

With April on the books, the total 2019–2020 season snowfall ranged from over 50 inches in far northern Illinois to less than 1 inch in southeastern Illinois. Most areas of the state north of Interstate 70 experienced a snowier than average season (see maps below).


Short-term 8–14-day outlooks from the NOAA Climate Prediction Center show strongly elevated odds of below normal temperatures and slightly elevated odds of above normal precipitation across the state.

Longer-term 30-day outlooks are similar to the 8–14-day outlooks, with continued, albeit weaker, chances of cooler and drier conditions, especially for the northeastern half of the state for May. 


April 2019: An Active Weather Pattern and Late Season Snow!

April 2019 will be a month remembered for a continuation of an active and stormy weather pattern across Illinois, with two short lived, yet notable and uncommon late season snow events which impacted many in northern portions of the state.

The month finished noticeably wetter than average, with temperatures marginally below the long-term average. The preliminary average statewide April temperature was 52.0°F, which is 0.6°F below the long term average. The preliminary average statewide precipitation was 4.58 inches, which is 0.80 inches above the long term average.

Note: Data are provisional and may change slightly over time.


Preliminary statewide average precipitation for April was 4.58 inches, which is 0.80 inches above the long term average.

Precipitation in Illinois has been above average since December 2018. Preliminary data would rank this as the 7th wettest December – April period in state history. The end of April 2019 marked six months since any portion of the state has been classified as in drought, or abnormally dry by the U.S Drought Monitor..

An active spring weather pattern resulted in a majority of regions in northern, eastern, and southern portions of the state receiving over 100% of average monthly precipitation, with localized amounts approaching 200%.  Smaller regions of the state in west-central Illinois – roughly between the Mississippi and Illinois rivers are the only locations to receive near or below average precipitation for the month (see map below).

The heaviest precipitation fell in extreme southern Illinois, especially in counties bordering the Wabash and Mississippi Rivers, where 6 to 8+ inches were common (see map below).  The highest total in the state was reported at a station near Cobden (Union County) with 8.31 inches.

Heading into May, flooding remains an ongoing concern for the state, as soil moisture percentiles remain in the 90th to 95th percent range.

As of April 30th, 134 river gauges affecting Illinois were reported with crests in minor, moderate, or major flood stages. The greatest threat continues to remain along the Mississippi River. River flooding concerns were intensified by several days or heavy rains during the last week of April.


A majority of April snowfall came from two short lived, yet notable late season events that impacted many in northern portions of the state.

The first event on the weekend of April 13th and 14th brought widespread reports of 1 to 5 inches along a corridor extending from near Quincy, and running northeast toward Chicago and the Illinois/Wisconsin border. Several localities west and north of Chicago reported 6 to 8+ inches. Notable accumulations were measured as far south as Peoria. An accumulation of 5.4 inches at Chicago O’Hare Airport tied the record for the snowiest calendar day this late in the season.  April 16, 1961 also recorded 5.4 inches of snow.

The second snow event on April 27th brought a variety of wintry precipitation types to locations in northern Illinois, including another round of accumulating snow for many from Chicago and points north and west.  With 3.7 inches, this was the latest 2+ inch snow event on record for Rockford (Winnebago County).

The maximum monthly snowfall in Illinois was reported at a station near St. Charles (Kane County) with an impressive 13.5 inches.


Preliminary results show that April 2019 finished with a statewide average temperature of 52.0°F which is 0.6°F below the long term average.

Despite several significant temperature swings throughout the month, which are common during springtime, statewide April temperatures finished right around the long term average. A few pockets in extreme southern Illinois reported slightly above average, and sporadic regions in northern Illinois reported slightly below the long term average.  This is a welcome change from last year,  April 2018, which ranked as the second coldest April on record.

The highest temperature in the state was recorded at a station near Jerseyville (Jersey County) with a reading of 85°F on April 23.  In contrast, the lowest temperature of 18°F was recorded at a station in Altona (Knox County) on April 1.

May 2019

Looking ahead at the rest of May 2019, the Climate Prediction Center (CPC) is favoring probabilities of above average temperatures for the southeast half of the state, with equal chances of above, near, or below average temperatures for the northwest half of the state. Unfortunately, an active weather pattern looks to persist, as the May outlook favors probabilities of above average precipitation statewide.

Late April 2019 Snow Event

4/29/2019 – A strong and considerably cold low pressure system took aim at Illinois on Saturday April 27th, bringing a large area of widespread precipitation and unseasonably cool weather to a majority of the state.  The greatest impacts were felt in Northern Illinois, where temperatures were cold enough to support a variety of wintry precipitation types. This included a late season and uncommon accumulating snow for many from Chicago and points north and west.

According to the National Weather Service, the final snowfall total at Chicago O’Hare of 2.5 inches was the latest accumulating snowfall for the city since 1989, and the latest 2+ inch single calendar day snowfall in station history. The two day period of May 1-2, 1940 saw 2.2 inches.

Typically, Chicago O’Hare can expect 1.2 inches of snow in April, with the record for the month being 11.1 inches which was set in April 1975.  To date, April 2019 has seen 7.9 inches.

The official snowfall total in Rockford of 3.7 inches was the latest accumulating snow since 1994, and ranks as the latest 2+ inch snow event on record.  Beating out April 23, 1986 with 3.8 inches, and April 23-24, 1910 with 2.5 inches.

A station in Stockton (Jo Daviess County) reported 6.0 inches of snow with this event.  See the interpolated map below of preliminary snowfall accumulation across the state. (Note: Locally higher snowfall reports were common)

Behind this system, and with the aid of fresh spring snow cover, temperatures dropped across Northern Illinois, with Rockford tying the record daily low temperature on the morning of April 28th with a reading of 28°F.

In total 26 weather stations reported temperatures below freezing on the morning of April 28th, with Stockton (Jo Daviess County) reporting the lowest weekend reading in the state with just 21°F.

April Already 4th Wettest on Record

Based on preliminary data, this April in Illinois is already the 4th wettest on record with 6.58 inches of precipitation. Average statewide precipitation for April is 3.77 inches. So we are already almost two inches above average.
According to the NWS forecast, more rain is expected across southern Illinois on Friday and Saturday. Therefore, it is possible that we will move up the list by the end of the month. In addition, some sites may have already reached their record for April, including the city of Chicago.

Top 5 Wettest Aprils

  1. 2011 with 7.40 inches
  2. 1957 with 7.13 inches
  3. 1927 with 6.95 inches
  4. 2013 with 6.58 inches
  5. 1944 with 6.50 inches

Precipitation Pattern Across the State

Here is how the precipitation has been distributed around the state, based on our multi-sensor precipitation product, with the actual amounts and the departures from average. Many parts of central and northern Illinois have more than double their average April precipitation (shades of purple in the second map).

April precipitation in inches for the first 24 days of the month. Click to enlarge.
April precipitation in inches for the first 24 days of the month. Click to enlarge.

April precipitation as departures from average. Click to enlarge.
April precipitation as departures from average. Click to enlarge.