July 2017 Weather and Its Impacts on Missouri

Pat Guinan
State Climatologist
Commercial Agriculture/University of Missouri Extension

The overall weather conditions in Missouri for July was hotter and drier than normal, but there was notable variability in areas of the state. Preliminary data indicate the statewide average temperature for the month was 78.7°F, or 1.1 degrees above the long-term average, Figure 1. Some areas of the state were hotter than others with highest positive departures over east central and north central sections, Table 1.

July 2017 Average Temperature, Departure From Normal
Station Name County
July 2015 Avg. Temp (°F) Departure From Normal (°F)
St. Joseph Buchanan 78.5 +1.4
Kirksville Adair 77.9 +2.8
Hannibal Marion 78.2 +1.8
Kansas City Platte 79.1 +0.8
Columbia Boone 79.2 +1.9
St. Louis St. Louis 84.3 +4.3
Springfield Greene 79.7 +1.5
Vichy/Rolla Phelps 78.0 +0.7
West Plains Howell 79.1 +1.1
Cape Girardeau AP Scott 79.0 +0.4
Table 1.

Some of the hottest temperatures experienced in 5 years occurred during a 5-day heat wave from July 18-22. High heat indices accompanied the hot weather and made it particularly challenging for people without air conditioning and outdoor laborers. The urban environment of St. Louis was particularly uncomfortable with triple digit heat on 4 consecutive days, including a record high of 108° on the 22nd of the month, Figure 2. July 2017 ranked as the 8th hottest July on record for St. Louis. The warmer than average month follows a warm trend that has been ongoing for nearly two years, Figure 3.

Rainfall was highly variable across the state, but the statewide average total was 3.38 inches, or 0.44 inches below the long-term average. Wettest conditions, where more than 4-inches were reported, were found over portions of northwestern, west central, central and southeastern Missouri. Driest locations, where less than 2-inches were observed, occurred along Highway 36 in northern Missouri, from St. Joseph to Hannibal. Another dry corridor extended from St. Louis southwestward to Texas County, in south central Missouri, on westward to just east of Joplin, MO, Figure 4. Some of the heaviest and lightest monthly rainfall totals around the state are listed in Table 2.

July 1-31, 2017 Rainfall reports
(NWS Coop and CoCoRaHS)
Station Name County
July 1-31 Precip (in.)
Kansas City South Jackson 11.63
North Kansas City 0.6 NNW Clay 11.14
Odessa 1.9 ENE Lafayette 10.60
Pleasant Valley 0.8 NW Clay 10.44
Elm Johnson 10.29
Raymore 1.2 SE Cass 10.18
Potosi Washington 0.43
Kirksville Regional AP Adair 0.92
Caplinger Au Gris L&D Lincoln 1.00
Arnold 0.5 E Jefferson 1.03
Cameron De Kalb 1.05
Marshfield 4.1 WSW Webster 1.10
Table 2.

According to the Drought Monitor map, drier conditions had expanded in Missouri since the end of June, especially over southern, east central and northeastern sections of the state, Figure 5. Moderate drought was depicted from St. Louis County southwestward to Crawford County. Many pastures in this region were in very poor condition, Figures 6 and 7.

On July 12-13 an extreme rain event impacted portions of northwestern and north central Missouri, from Grundy to Linn counties. An observer residing 1.3 miles east-southeast of Jamesport, in Daviess County, reported 9.30 inches the morning of July 13. Another observer residing 5.5 miles south-southeast of Trenton, in Grundy County, reported 8.68 inches that morning. Flash flooding was reported in the area.

Another extreme rain event impacted west central Missouri on July 26-27, including the Kansas City metro area, with several locations reporting 4-7 inches. Heaviest reports of more than 8-inches were observed in Johnson County (Odessa, 6.7 SSW, 8.52"), Lafayette County (Odessa, 1.9 ENE, 8.60") and Clay County (Gladstone, 1.1 NE, 8.75"). Major flash flooding occurred during the event with numerous water rescues reported around the Kansas City area. Fortunately, there were no casualties.

According to the Missouri Agricultural Statistics Service report from July 30, 2017, 59% of the state reported topsoil moisture supplies in adequate condition with 35% of the state reporting topsoil moisture in short condition. Statewide subsoil condition was reported 68% adequate. Corn, soybean and pasture conditions were reported at 61%, 65%, and 50% in good to excellent condition, respectively. The majority of hay and stock water supplies were adequate to surplus.

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Missouri Average July Temperature 1895-2017*

Figure 1.

St. Louis, MO July Daily Max/Min Temperature Normal vs. 2017

Figure 2.

Missouri Monthly Temperature Departure from Average* Jan 2016 - Jul 2017**

Figure 3.

Missouri Radar Estimated Rainfall(in.) for July 2017

Figure 4.

U.S. Drought Monitor Missouri

Figure 5.

Washington County

Figure 6. Washington County, near Potosi, Missouri, Photo: Rachel Hopkins
Crawford County

Figure 7. Crawford County, near Dillard, Missouri, Photo: Rachel Hopkins

Average Temperature
Average Temperature: Departure from 1981-2010 Normals

Accumulated Precipitation (in)

Accumulated Precipitation (in): Departure from 1981-2010 Normals

Source: Pat Guinan, 573-882-5908