The afternoon high temperature for Sioux City was a couple degrees warmer than Des Moines. The featured chart compares the two sites for this temperature metric. The top panel shows a heat map by week of the year for this temperature difference with a line showing the weekly average value. The bottom panel plots the temperature difference by the afternoon average wind speed. So what's interesting about the chart is that the spring and fall seasons are the most favored times for Sioux City to warmer than Des Moines. This is likely due to Sioux City being a bit more of a high plain climate than Des Moines, so is able to warm more during the least humid and strongest solar heating times of the year.

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