The Iowa Environmental Mesonet (IEM) collects environmental data from cooperating members with observing networks. The data are stored and made available on this website.
Two-Thirds of Monthly Average
Posted: 21 Aug 2025 05:30 AM, Views: 626Even with about ten days to go for August, most of the state is already above average for rainfall for the month. August will finish as yet another wet month during 2025. For Ames, only the months of January and February were substantially below their respective long term averages. The monthly reliability of being at or above some average accumulation is the subject of today's featured chart. The chart presents the percentage of years over the past 30 that had a monthly precipitation accumulation of at least 66% of the climatological average. The months of March and October show up as being the least reliable and May being the most. While the differences are not all that large, it is interesting to see how comparable the spring and fall seasons are vs winter and summer. Getting sufficient rainfall during July and August is certainly important to production agriculture as moisture stress negatively impacts yields. You can generate this chart for different sites, periods, and your arbitrary percentage threshold of your choice and see if you can spot any trends!
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2008Moisture returns
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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.