The Iowa Environmental Mesonet (IEM) collects environmental data from cooperating members with observing networks. The data are stored and made available on this website.
Boone County Corn Yields
Posted: 23 May 2025 05:30 AM, Views: 1017
Tags: corn
With USDA NASS's recent release of 2024 county corn yield estimates, it is a good time to plot up a bit of a deep dive comparing yearly yields and weather metrics. The featured chart combines the Boone County NASS corn yields with the long term Ames climate site data. As as aside, while Ames is mostly in Story County, the long term climate site was at the research farm west of town in Boone County for a good chunk of the period of record data. The top left panel shows the yearly yield values along with a linear trend line, trailing 10 year average, and simple mean plotted. The lower left panel plots the yearly departure against the 10 year trend line. The three worst and three best years against the trend are assigned special markers for the right side eight panels presenting various weather metrics between 1 May and 30 September. The bottom two right side panels tell a good story with too little and too much precipitation being negative for corn yields along with increasing Stress Degree Days (SDD)s decreasing yields. Of course, there is no magic metric between weather variables and corn yields, but it is certainly fun to play around with the data and see if you can spot any trends. You can follow the "generate this chart" link and generate more charts like this for your periods and location of choice.
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Previous Years' Features
2024: Greenfield Tornado
2023: Weather Three-Peat
2022: Bias Correction Attempt
2021: 60+ Degree Dew Points
2017: Cold Air Above Us
2016: None to three inches
2013: Comfortable Dew Points
2012: May Precipitable Water
2011: 70s and 90s
2010: Dew points ramping up
2007: 4 inches in 50 miles
2006: Welcome back MCS
2005: Smooth Curves
2002: Cool Friday
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Soil Temperatures

Data from the Iowa State Soil Moisture Network is found on this website and daily soil temperature averages are used to produce the highlighted analysis.