90+ Degree Days

Posted: 04 Oct 2024 05:30 AM, Views: 854
The current forecast has parts of Iowa taking a run at 90° high temperatures this weekend, so it is a good time to check in on the accumulated number of such days each year. The featured chart presents the number of days with a high temperature of at least 90°F for Ames. Each year's bar is colored by either being above or below the simple long term average number of days. The yellow line presents a trailing 30 year average. The long term trend has been downward, but that is largely explained by land use changes modifying the surface energy budget and summer time increases in humidity. It is interesting to see the recent and modest increase in number of days over the past five years or so and if that trend will continue over the coming decade or so.
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