Iowa 7-Day Forecast: Highs Near 90°F Early, Easing to Low 80s by Weekend

What changed

The National Weather Service (Des Moines office) forecast for central Iowa shows a two-phase week:

Hot start (Tue–Thu):

• Today (Tuesday): High 89°F, low tonight 70°F
• Wednesday: High 90°F, low 70°F
• Thursday: High 89°F, low 69°F

Cooler finish (Fri–Mon):

• Friday: High 83°F, low 66°F
• Saturday: High 83°F, low 65°F
• Sunday: High 84°F, low 66°F
• Monday: High 86°F, low 69°F

That's roughly a 6–7°F drop in daytime highs from midweek to the weekend, and overnight lows dip from around 70°F into the mid-60s.

Why it matters

Late July is prime pollination time for much of Iowa's corn crop. Daytime highs in the upper 80s to 90°F paired with overnight lows near 70°F can add stress during silk and tassel. The shift to low-80s highs and mid-60s lows by Friday could give pollinating fields some relief. Cooler nights in particular may matter for pollen viability and plant recovery.

This forecast is based on the NWS Des Moines (DMX) grid point and represents central Iowa conditions. Temperatures across the state will vary — check your local NWS office for field-level detail.

What to watch next

• Whether the midweek 89–90°F readings hold or push higher — even a degree or two above 90°F changes the stress picture.
• How quickly the cool-down arrives Friday and whether it sticks into the following week.
• Rainfall chances (not covered in this temperature-only snapshot) — heat plus dry is a different story than heat plus moisture.

Source notes

All temperatures from the U.S. National Weather Service API, Des Moines (DMX) office grid point forecast, retrieved July 28, 2026. NWS API link