Do chilly nights correlate to frosty mornings?

SIOUX FALLS, S.D. (KELO) -- We're seeing chillier nights more often now that we're in late October.

Meteorologist Adam Rutt explains why a chilly night doesn't necessarily mean a frosty night.

Portions of eastern KELOLAND saw their first near and sub-freezing temperatures of the season last night, and while that can certainly be considered a figuratively frosty night…not everyone could take that literally. There are a few reasons why chilly temperatures aren't the only ingredient needed for frost to develop.

While chilly temperatures are certainly needed, there are a few more things that we need. First, we need a calm night. Brisk conditions at the surface circulate the wind at the surface and allow it to mix with drier air aloft.

That leads into the second ingredient: Low-level moistu