Excessive Heat — Sioux, Iowa

2025-08-08 · Sioux, Iowa

Event narrative

Dangerous heat index values peaked as high as 108 degrees at Hawarden and 104 degrees at Sioux Center.

Wider weather episode

High levels of moisture pooled along and ahead of an outflow boundary across eastern South Dakota and southwest Minnesota with dew point readings into the the upper 70s to lower 80s. With temperatures in the upper 80s to lower 90s, heat index values generally reached the 100 to 110 degree range during the mid afternoon to early evening.

Source: NOAA Storm Events Database, event_id 1291006. Narrative written by the NWS forecast office that issued the report.