Iowa 7-Day Forecast: Highs Climb From 89°F to 96°F Through July 18

What changed

The National Weather Service forecast for central Iowa (Des Moines area) lays out a week of rising heat:

• Today (Sat Jul 12): High 89°F, tonight's low 66°F
• Monday Jul 13: High 92°F, overnight low 69°F
• Tuesday Jul 14: High 94°F, overnight low 71°F
• Wednesday Jul 15: High 95°F, overnight low 73°F
• Thursday Jul 16: High 96°F, overnight low 74°F
• Friday Jul 17: High 96°F, overnight low 76°F
• Saturday Jul 18: High 96°F, overnight low 74°F

Highs push into the mid-90s by midweek and stay there through the weekend. Overnight lows climb too — from 66°F tonight to 76°F by Friday night.

Why it matters

Mid-July is when a big share of Iowa corn is pollinating. Daytime highs in the mid-90s paired with overnight lows in the 70s mean the crop doesn't get much of a cool-down between days. That combination could affect pollen viability and silk receptiveness, especially in fields that are also short on moisture.

For soybeans moving into early pod set, the same heat may matter for flower retention. The rising overnight lows are worth watching closely — nights that stay above 70°F reduce the plant's chance to recover from daytime stress.

What to watch next

• Updated NWS forecasts later this week — any shift toward cooler air or rain chances could change the outlook.
• Local soil moisture — heat stress effects depend heavily on whether fields have adequate water. Check your own rain gauge and local mesonet stations.
• Crop condition reports — USDA's weekly Crop Progress report (typically Monday afternoon) may reflect early stress signs if this heat holds.

Source notes

All temperature data from the U.S. National Weather Service API, Des Moines (DMX) forecast office grid point. Forecast issued for the period July 12–19, 2026.