10:30pm update: The Freeze Warning has expanded into northern Iowa. The light blue counties (see picture) are the Freeze Warning; the purple counties are the Frost Advisory.
Lows will fall to around 25-30° in the Freeze Warning area. Lows in the Frost Advisory area will tumble to about 30-35°. If you want to keep those plants going for a bit yet, cover them up or bring them in.
Additionally, frost will be likely again Sunday night.
Typically, the first frost for the area is right around this time. The good news is that it looks like we’ll have a nice, pleasant, “Indian summer”-ish week next week!