The forgettable week of blistering hot weather for Iowa has mostly come to an end this Sunday. The high temperature in Des Moines hit 100+ degrees for four straight days, but only on Saturday did it tie a previously set record. The featured chart presents the dates and years of daily high temperature records being set or tied. Of note, is the lack of events in July as shown by the highlighted area. In fact, it has been since 1955 that a record was either tied or set in July for Des Moines! The plot overall shows a lack of new records in the summer months. A common explanation for this is that our increased agricultural activity has increased dew points during the summer months through increased plant transpiration. Heating this moisture rich air takes more energy and acts to suppress high temperatures in the mid afternoon. Or others may say that the dust bowl era (1930s) rewrote our summertime records to levels that will be very difficult to exceed without another organized large scale drought event.

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Tags:   jul12   july