October 2018 Weather and Its Impacts on Missouri

Pat Guinan
State Climatologist
University of Missouri Extension

Anomalous autumn warmth persisted through the first nine days of October with a notable pattern change toward cooler, below average conditions for the remainder of the month. Preliminary data indicated the statewide average October temperature was 56.4F, or 0.6 below the long-term average. It was the first time in 5 years for a cool October, Figure 1, and the first below average month since April 2018, Figure 2.

October conditions were wet, especially across northern sections, and portions of central and south central Missouri. The statewide average rainfall total was 4.90 inches, or 1.69 inches above the long-term average. It was the wettest October in four years, Figure 3, and the fourth wetter than average month for the year, Figure 4.

Some northwestern and north central counties reported more than 10-inches for October; it was the hydrological antidote to eliminate drought impacting the region for over a year. Some northern Missouri counties reported 20-25 inches of rain from mid-August to mid-October, which was similar to totals accumulated for 12-months prior to mid-August. By the end of October, drought conditions significantly improved statewide. The improvement is especially notable when compared to drought status in mid-August, Figure 5.

The wet weather during the first half of the month limited opportunities for crop dry-down and harvest, however drier conditions during the latter half allowed fieldwork activity to resume. According to the Missouri Agricultural Statistics Service, for the week ending October 28, corn and soybean harvest was 90% and 51% complete, respectively; 7 percentage points ahead of the 5-year average for corn but 10 percentage points behind for soybean. The majority of topsoil and subsoil moisture conditions were reported adequate at 85% and 74%, respectively. Pasture conditions were mostly fair (38%) to good (31%). However, hay supplies were mostly short (32%) to very short (37%). Stock water supplies were mostly adequate (76%). The wetter October conditions, in combination with mild weather during the first half of the month, translated to some rejuvenation of warm season grasses over parts of the state.

Freezing weather was reported across most of Missouri during the latter half of the October. The northern 2/3 of Missouri experienced temperatures ≤32F in mid-October. Another freeze event during the morning of Oct 21 impacted most of the state, with the exception of the Bootheel and a handful of locations in far southwestern Missouri. Median spring and autumn dates for specific freeze thresholds in Missouri can be found at http://ipm.missouri.edu/FrostFreezeGuide.

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Missouri Average October Temperature 1895-2018*

Figure 1.

Missouri Monthly Temperature Departure from Average* January 2017 - October 2018**

Figure 2.

Missouri Average October Precipitation 1895-2018*

Figure 3.

Missouri Monthly Precip Departure from Average* January 2018 - October 2018**

Figure 4.

US Drought Monitor Missouri August 14 and October 30, 2018

Figure 5.

Missouri Average Temperature October 1 to October 31, 2018

Missouri Average Temperature Departure October 1 to October 31, 2018

Missouri Accumulated Precipitation October 1 to October 31, 2018

Missouri Accumulated Precipitation Departure October 1 to October 31, 2018

Source: Pat Guinan, 573-882-5908