A tale of two vegetable growing seasons told by two west Michigan weather stations

Weather challenged west central Michigan vegetable growers in different ways in 2012 and 2013.

National Weather Service stations in Hart, Mich., and Grand Rapids, Mich., have collected weather data for the past 50-plus years and show how different the past two years have been for our west Michigan vegetable growers. Overall, heavy spring rainfall dominated the weather story in 2013 while hot, early spring weather followed by dry weather dominated news in 2012. Rainfall patterns were much different in 2013 compared to 2012. In 2013, April rainfall was extremely high with recorded totals 4 inches above the 3.06-inch normal at the Hart station and 8 inches above the 3.35-inch normal at the Grand Rapids station. In fact, this was the wettest April ever in the 101 years of record at the Hart station and over 50 Aprils at the Grand Rapids station.

The heavy rainfall flooded low-lying areas, including muck vegetable fields in Kent, Newaygo, Ottawa and Allegan counties, which delayed planting in many areas. To the north, it delayed digging of asparagus crowns and planting of carrots by weeks even on typically high-and-dry sandy soils. In contrast, 2012 spring rainfall was close to or below normal though July at the Grand Rapids station, while rainfall was more variable at the Hart station, but dry at times.

Data from 2012, 2013 and 30-year normals of monthly rainfall from the Hart, Mich., National Weather Service observing site.
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Data from 2012, 2013 and 30-year normals of monthly rainfall from the Grand Rapids, Mich., National Weather Service observing site at the International Airport.
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In 2012, high early spring temperatures and a warmer than normal growing season dominated the weather news, while temperatures were more normal throughout the 2013 season. Recorded mean temperatures were 15 degrees Fahrenheit above normal for March 2012 due to an early period of summer-like weather. These were the highest March mean temperatures on record for the 101 and 50 years the Hart and Grand Rapids stations have complete data for, respectively. These high temperatures led to challenges in perennial crops as plants developed abnormally early and then were frosted as temperatures dropped back to more normal levels. Recorded temperatures were also high in July 2012 corresponding to a period of dry weather in Grand Rapids, leading to water stress in area crops. In contrast, 2013 mean temperatures were closer to normal for the majority of the growing season.

Data from 2012, 2013 and 30-year normals of average monthly temperatures from the Hart, Mich., National Weather Service observing site.
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Data from 2012, 2013 and 30-year normals of average monthly temperatures from the Grand Rapids, Mich., National Weather Service observing site.
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Another major difference in temperatures was apparent between years: the last spring and earliest fall freezing temperatures were recorded very late in 2013 compared to 2012, shifting the growing season to later in the calendar year. In fact, only 7 percent of the 107 years of data from the Hart station have freezing temperatures been recorded as late as the May 25, 2013 date. Similarly, only 9 percent of the 50 years for which data are available from the Grand Rapids station recorded freezing temperatures as late as May 13, the date observed in 2013. Brief periods of cool weather like this can have major consequences for vegetable crops by causing freeze damage and can also slow establishment of transplanted vegetables.

Just as striking, the date of the earliest recorded freezing temperature in fall 2013 was relatively late in October. Only 3 percent of the 107 years of data from the Hart station recorded freezing temperatures as late as the fall 2013 date of Oct. 23. Similarly, only 4 percent of the 50 years of data from the Grand Rapids station recorded freezing temperatures as late as the fall 2013 date of Oct. 25. The mild fall likely helped make up for the late start in planting.

Michigan State University Extension recommends visiting the Enviro-weather website to access more weather data specific to your growing region, including Hart, Mich., and models that help predict how changes in weather affect pest and disease development in fruits and vegetables.

Data from the Hart, Mich., National Weather Service station on first and last dates of below freezing temperatures.

Weather variable

2012

2013

Last spring freezing temperature

April 30

May 25

First fall freezing temperature

Oct. 8

Oct. 23

% of years in 107 years of data with spring freeze this late

39%

7%

% of years in 107 years of data with fall freeze this late

21%

3%

Date from the Grand Rapids, Mich., National Weather Service station on first and last dates of below freezing temperatures.

Weather variable

2012

2013

Last spring freezing temperature

April 29

May 13

First fall freezing temperature

Oct. 8

Oct. 25

% of years in 50 years of data with spring freeze this late

33%

9%

% of years in 50 years of data with fall freeze this late

26%

4%

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