Missouri 2021 Growing Season Climate Summary
Pat Guinan, MU Extension/State Climatologist
In general, Missouri experienced a favorable growing season in 2021.
Roller coaster temperatures characterized April with weeks 1 and 4 averaging above normal and cooler conditions for weeks 2 and 3. Official data indicate a statewide average temperature of 54.2 °F, or 0.3 degrees below the baseline period mean (1901-2000). Three out of the past four Aprils have been cooler than average.
An unusually cold weather event on April 21-22 brought sub-freezing temperatures to the state, including record low temperatures. Freeze damage was reported to vegetation in vulnerable growth stages, including some early planted corn in southeastern Missouri, as well as some fruit crops, ornamentals and annuals. Lodging of forage crops was also reported.
April precipitation was above average with a statewide average total of 4.36 inches, or 0.39 inches above the baseline period mean (1901-2000). Mostly wet conditions impacted Missouri for the first quarter of the year with 3 out the past 4 months reporting above average precipitation.
An unusual late spring snow event impacted Missouri on April 20-21. Accumulations were generally 1-5 inches statewide, occurring mostly on elevated and grassy surfaces.
According to the Missouri Agricultural Statistics Service, for the week ending April 25, corn planting was 23% complete, 21 percentage points behind the 5-year average. Stock water supplies were reported mostly adequate at 94% with 81% of the hay supplies and other roughages adequate and 6% surplus. The majority of pastures, 67%, were in good condition and 27% in fair condition. Topsoil moisture supplies were mostly adequate (82%) to surplus (17%) statewide. Subsoil moisture supplies were mostly adequate (87%) to surplus (12%).
Cool was the rule in Missouri during May, especially with maximum daily temperatures remaining below average. The statewide average temperature was 62.3°F, or 1.9° below the long-term average. The cool conditions were similar to May weather the previous year and it was the second consecutive cool month and third below average month for 2021.
May precipitation was variable across Missouri, ranging from 2-3 inches in some east central counties to more than 10-inches in parts of west central and southwestern Missouri. The statewide average total of 4.99 inches was 0.33 inches above the long-term average. The wet conditions followed the trend over the past few decades. Since 1990, 22 Mays, or 69% of them, have been wetter than average. Four out the five wettest Mays on record have occurred since 1990.
There were several May days in 2021 with cloudy, showery weather, especially during the latter half of the month. Several locations experienced measurable rainfall and overcast conditions for more than half the days in May.
According to the Missouri Agricultural Statistics Service, as of May 30, 2021, 92% of the corn and 49% of the soybean crop had been planted; the 5-year average is 91% and 53%, respectively. The cool, cloudy weather generally benefited pastures with 71% of them reported to be in good condition and 6% excellent. Hay supplies and other roughages were listed at 85% adequate and 4% surplus. Stock water supplies were reported mostly adequate at 87% and 13% surplus. Topsoil moisture supplies were mostly adequate (57%) to surplus (42%) statewide. Subsoil moisture supplies were mostly adequate (74%) to surplus (25%).
The statewide average monthly temperature for June was 74.8°F, or 1.8 degrees above the baseline average (1901-2000). The warmer than average temperatures followed the trend over the past several years, where only one June since 2005 has been below average.
Dry and hot conditions emerged during the first few weeks of June and producers were concerned since critical corn growth stages were approaching. A pattern change, however, during the third week shifted concerns from impending drought to flooding. The majority of rainfall occurred during the last 12 days of June and a few locations reported their wettest June in decades. Columbia Regional Airport reported 0.10" between June 1-19, but received 10.85 inches for the month, making it the 2nd wettest June since 1890 and wettest June since 1928 when 14.86 inches was reported.
June rainfall was above average statewide, but variable across Missouri, ranging from 10-15+ inches in parts of northwestern and central Missouri to less than 2-inches over portions of southern Missouri, according to radar estimates. The statewide average rainfall total was 5.98 inches, 0.96 inches above the baseline average (1901-2000).
The extraordinary amount of rainfall that fell over parts of the state during the last 12 days of June resulted in thousands of acres of flooded low-lying fields and bottomlands. Nitrogen deficiencies in corn were also reported. Alternatively, pastures had greened up nicely with the cooler temperatures and abundant rainfall.
The wetter conditions toward the end of June resulted in no drought for the Show Me State, according to the U.S. Drought Monitor. There were a couple areas showing abnormally dry conditions, including a few northwestern counties bordering Iowa and a thin corridor in southeastern Missouri, extending from Ste. Genevieve and Perry Counties southwestward to parts of Carter and Shannon Counties.
According to the Missouri Agricultural Statistics Service, for the week ending June 27, 2% of the corn was silking compared to a 5-year average of 15%. Soybean was 96% planted, compared to a 5-year average of 91%. Topsoil moisture supplies were rated 86% adequate to surplus and subsoil moisture was rated at 91% adequate to surplus. Corn was rated mostly good to excellent at 58% and soybean was reported at 57% good to excellent. Pasture conditions were mostly good to excellent at 72%. The majority of hay supplies and roughages were adequate at 81%. Stock water supplies were reported to be in adequate (85%) or surplus (12%) condition.
Seasonably cool temperatures impacted Missouri in July with data indicating a statewide average temperature of 76.6°F, or 1.1° below the long-term average. Daily maximum temperatures for July were mostly below average, generally climbing into the 80s. There was a period of hotter weather during the last week of the month when temperatures reached into the 90's. With one exception, there was no triple digit reported statewide during the entire month. A cooperative observer located 2 miles west of Cosby, MO, in Andrew County, reported a high temperature of 100°F on July 30th.
Minimum July temperatures were mostly in the 60's with some 70's reported toward the end of the month. There were more above average minimum temperature days than maximum temperature days due, in part, to above average dew point temperature. High dew points elevate minimum air temperatures while suppressing maximum temperatures. The high July dew points this year followed the trend Missouri has experienced over the past few decades.
The statewide average July rainfall total was 4.86 inches, or 1.15 inches above the long-term average. It was the fifth consecutive month with above average precipitation.
According to radar-estimates, heaviest July rainfall occurred over portions of northeastern and southeastern Missouri where 5-8 inches were common. A few areas reported more than 10-inches for the month. Driest conditions were across parts of northwestern and west central Missouri and a few isolated pockets in southern sections.
According to the Missouri Agricultural Statistics Service report for the week ending July 25, 2021, 10% of the state reported topsoil moisture supplies in short to very short condition with 84% of the state reporting topsoil moisture in adequate condition. Statewide subsoil condition was reported 5% short to very short, and 89% adequate. Corn, soybean and pasture conditions were reported at 8%, 9%, and 3% in poor to very poor condition, respectively. The majority of corn and soybean were reported in good to excellent condition at 66% and 61%, respectively. The majority of pasture was in good to excellent condition at 75%. The majority of hay and other roughages were adequate to surplus (93%), as well as stock water supplies (97%).
All of Missouri was "drought-free", according to the U.S. Drought Monitor, released on July 29, 2021. There was a small area of abnormally dry conditions reported in southeastern Missouri, impacting some southeastern Ozarks counties.
Above average daily August temperatures impacted Missouri with a statewide average temperature of 77.4°F, or 1.4° above the long-term average. It was the hottest August in a decade. Below average temperatures occurred during the first week of August and were followed by warmer than average conditions for much of the rest of the month, including several days with high temperatures in the 90s and lows in the upper 60s and lower 70s. Most locations, again, reported no triple-digit heat for the month.
Daily summer temperatures in 2021 reflected the overall trend of the past few decades, with no prolonged periods of extreme high temperatures. Mean summer temperature data (Jun-Jul-Aug) indicate slightly above normal conditions in 2021. The statewide average summer temperature was 76.3°F, 0.8° above the long-term average. Summer weather patterns over the past several decades indicate little change in maximum temperature trends, whereas minimum summer temperatures have been warming. This phenomenon is primarily due to above average summer dew point temperatures in Missouri.
Drier than average weather impacted Missouri in August with a statewide average of 2.99 inches, 0.72 inches below the long-term average. Typical of the summer season, August rainfall was highly variable, ranging from less than 1-inch to over 11-inches, according to rain gauge observations. Most areas received below average rainfall. Radar estimates indicated pockets of more than 5-inches in parts of the state but most locations received less than 3-inches.
The U.S. Drought Monitor map, for the week of August 31, 2021, indicated small areas of abnormally dry conditions impacting parts of central, southwestern and southeastern Missouri.
According to the Missouri Agricultural Statistics Service report for the week ending August 29, 2021, 67% of the state reported topsoil moisture supplies in adequate condition with 2% surplus, whereas 27% of Missouri reported short topsoil moisture supply and 4% very short. Subsoil moisture supplies were reported 74% adequate and 2% in surplus condition compared to 21% of the state reporting subsoil moisture supplies short and 3% very short. Corn was reported 63% in good to excellent condition compared to 77% last year. Soybean was reported 59% in good to excellent condition compared to 75% last year. Pastures were rated at 60% in good to excellent condition compared to 55% last year. Hay and other roughages were 91% adequate to surplus compared to 87% last year. Stock water supplies were 89% adequate and 11% short to very short.
Summerlike weather continued into September with above average daily temperatures for most of the month. The statewide average September temperature of 71.6 °F was 3.4 degrees above the long-term average. The mild month followed the trend over the past decade with only 3 out of the past 10 Septembers being cooler than average
Dry conditions impacted most of Missouri in September with rainfall data indicating a statewide average of 2.35 inches, 1.75 inches below the long-term average. It was the second consecutive dry month with an August-September statewide average rainfall total of 5.34 inches, 2.47 inches below average, and the driest August-September period since 1999.
September rainfall totals were variable across Missouri with radar-estimates indicating highest amounts in parts of west central and southeastern Missouri and a driest conditions across portions of northern Missouri.
The U.S. Drought Monitor map for September 28, 2021 showed over half of Missouri experiencing abnormally dry conditions to moderate drought. Driest conditions were localized and impacting portions of southern Missouri.
According to the Missouri Agricultural Statistics Service, as of September 26, 2021, the majority of the corn crop was in good to excellent condition at 54% and 13%, respectively. Remaining corn conditions this year were 24% fair, 7% poor and 2% very poor. Corn harvest was on pace with the 5-year average at 34%. The majority of the soybean crop this year was also reported in good (56%) to excellent (8%) condition compared to 61% good and 20% excellent at the same time last year.
The majority of hay and roughages were adequate (85%) to surplus (5%) this year with 8% short and 2% very short. Stock water supplies were mostly adequate at 82%, with 15% short and 3% very short. The majority of pastures were reported in fair (41%) to good (40%) condition with 3% in excellent condition and 16% in poor or very poor condition.
The majority of topsoil moisture conditions were 52% adequate and 0% surplus while 40% were reported short and 8% very short. The majority of subsoil moisture conditions were also reported to be adequate (64%) to surplus (0%) with 31% short and 5% very short.
The statewide average October temperature was 60.5°F, or 3.5° above the long-term average. It was the warmest October since 2016. It was also the sixth above average month for the year and third consecutive month with above average temperatures.
Warm conditions dominated the first three weeks of October with high temperatures on many days reaching the 70s. Most of Missouri typically experiences its first fall freeze in October, but this year only a handful of locations in northwestern Missouri and the eastern Ozarks reported temperatures ≤32°F. Fall freezes occurring later than usual has been the trend over the past couple decades.
A wetter pattern returned in October with a statewide average precipitation total of 5.86 inches, or 2.67 inches above the long-term average. It was the wettest October since 2014 and ranked as the 9th wettest October on record.
According to radar estimates, most locations reported more than 5-inches for October with scattered pockets of 3-5 inches elsewhere. Lightest totals occurred in east central Missouri, around the St. Louis metropolitan area. The highest mean county rainfall estimate for the state was in Mercer County with 9.87 inches. St. Louis County and St. Charles County both reported the lowest total of 3.33 inches.
Occasional wet periods in October limited opportunities for crop dry-down and fieldwork activity, but favorable September weather had given producers a head start on harvest. According to the Missouri Agricultural Statistics Service, for the week ending October 31, corn and soybean harvest was 86% and 59% complete, respectively; 4 percentage points ahead of the 5-year average for corn and 2% points behind the 5-year average for soybean. The majority of topsoil and subsoil moisture conditions were reported adequate at 80% and 83%, respectively. Hay supplies were mostly adequate (87%) to surplus (4%) with only 8% reported short to 1% very short. Stock water supplies were mostly adequate (92%).
Wet and warm October conditions, and no hard freezes, mitigated livestock winter feed supply concerns with robust cool season grass growth reported. The U.S. Drought Monitor also indicated improving conditions by the end of the month, with only small residual pockets of dryness impacting the Show Me State.
Source: Pat Guinan, 573-882-5908