SIOUX FALLS, S.D. (KELO) — Hot and humid conditions led to very warm overnights in KELOLAND. It’s not too often we stay in the 80s overnight.

In fact, the overnight low in Sioux Falls fell to 81. Which ties a record for the warmest low temperature on record. The other mornings with a low of 81 were August 14, 1938, and July 12, 1936.

Other locations fell to the 70s in eastern KELOLAND with 60s in central and western South Dakota.

And it doesn’t happen that often. Since records have been kept in Sioux Falls, which dates back to 1893, having a low of 80 degrees or warmer has only happened 6 times.

Here’s a quick explainer on what typically happens when it comes to overnight lows.

During the day, the sun heats the earth which in turn heats the air around it. At night, heat rises to cool the surface.

In our case last night, we had many things combined to keep the mild air around. They included the height of the heat in the atmosphere was deep. High dew point temperatures in the 70s plus a southerly wind all helped keep us very mild.

But that will change tonight as drier air moved into southeast KELOLAND during the day. Sure it was another hot day, but the temperature tonight will be at least a little cooler.