Iowa 7-Day Forecast: 97°F Monday, Then a Cool-Down Into the Mid-80s

What changed

The NWS Des Moines forecast (DMX grid point) shows a big temperature swing this week:

• Today (Saturday): High of 89°F
• Tonight: Low near 71°F
• Monday: High of 97°F — the week's peak
• Monday Night: Low around 74°F
• Tuesday: High of 88°F
• Tuesday Night: Low near 65°F
• Wednesday: High of 83°F
• Wednesday Night: Low around 63°F

That's a 14-degree drop in daytime highs from Monday to Wednesday, and overnight lows fall from the mid-70s into the low 60s over the same stretch.

Why it matters

Mid-to-late July is prime pollination time for much of Iowa's corn crop. Daytime highs in the upper 90s can stress tasseling and silking corn, especially when nighttime temps stay warm and plants can't cool down. Monday's 97°F high paired with a 74°F overnight low is the tightest window of the week. The quick retreat to 83°F by Wednesday — with nights dipping to 63°F — could ease that stress considerably. For soybeans in the flowering and pod-set window, the cooler midweek stretch is also a more favorable range.

What to watch next

• Thursday through Saturday forecasts — the planner notes temps may warm back toward the upper 80s by next weekend. Updated NWS forecasts later this week will fill in that picture.
• Rainfall chances — temperature is only half the heat-stress equation. Soil moisture and any rain chances midweek are worth checking alongside these highs and lows.
• Local variation — this forecast is from the DMX grid point in central Iowa. Western and eastern Iowa may see slightly different numbers. Check your local NWS office forecast for field-level detail.

Source notes

All temperatures from the U.S. National Weather Service API, DMX grid point 73,49 forecast (api.weather.gov), accessed July 19, 2026.