SIOUX FALLS, S.D. (KELO) — Just when you thought it was safe to wave goodbye to frost, Mother Nature is saying “not so fast.”

While temperatures through the first half of the workweek will remain in the 70s and 80s for afternoon highs, much colder air is lurking. That cold air will move through the upper plains starting Thursday night in western South Dakota and it will settle in for everyone just in time for the weekend.

From this morning’s forecast, the temperatures will fall to the 30s by Saturday morning for almost everyone. Even Sunday gets in on the late season chill.

Factors that play a role in how cold we get include cloud cover, as clear skies at night generally mean colder air. Light winds allow the heat of the day to escape more efficiently. The recent moisture should help with warmer temperatures as it’s harder to cool wet ground compared to dry ground.

So, you’ll want to pay attention to the forecast if you put any flowers out or started your garden. Hopefully, the record cold stays away. For that to happen we’ll have to fall to the 20s.