December 2023 will be one of the warmest on record for the United States once preliminary data is calculated and compared to normal and records.  Average temperature departures across portions of the northern and central United States were greater than 5 degrees above normal. 

Meanwhile, areas of the northern United States experienced temperature anomalies almost 13 degrees above average, according to data provided by the PRISM Climate Group. 

Daily Mean Temperature Anomaly (credit PRISM Climate Group, OSU)

In many locations across the United States, December average temperatures ranked as the warmest on record.

Data from the Southeastern Regional Climate Center Perspectives Tool (Image to the right), indicates that cities such as Sioux Falls, Minneapolis, Fargo, Watertown, Duluth, Green Bay, Des Moines, Milwaukee, as well as many others experienced their warmest Decembers on record during 2023.   

You can interact with this map and data by clicking on the link here. 

Taking a closer look at the Tri-State region reveals a similar picture.  Record December temperatures were reported areawide, with many long term climate location setting new thresholds for December.   Here is a listing of a handful of cooperative observer reports that have arrived for the month of December, indicating new record warmth and high departure from normal values. 

Spencer, IA                32.9°  (+13.8°)
Le Mars, IA                32.9° (+10.5°)
Marshall, MN            31.8° (+12.9°)
Vermillion, SD           33.8° (+9.5°)
Menno, SD                32.7° (+9.8°)
Worthington, MN      31.0° (+11.2°)
Primghar, IA              34.1° (+10.8°)
Windom, MN            34.1° (+12.0°)

But the measure of the warmth of a month can be indicated in more than just the average temperature.  A few unique statistics were created during the month.    Overnight low temperatures in December are typically very cold.  While temperatures did fall below their normal at times, the coldest temperature recorded during the month in several locations was actually warmer than any other December month.  In Sioux Falls, for example, the coldest temperature during the month was 11 degrees.  Every December dating back to the beginning of records in the 1890s experienced a colder low temperature for the month than what was experienced in 2023.  

December is also a month that typically experiences many days below freezing for a high temperature.  However, in December 2023, many locations only experienced 1 or 2 days with high temperatures below freezing.  Our long term climate locations in Huron, Sioux Falls, Sioux City, and Mitchell all experienced the fewest days below freezing on record for December.