Calhoun CountyPower Outage History
2015–2025 · Iowa
Average — typical outage frequency and duration nationally.
Outages by year
Outages by month (seasonality)
Worst outage events on record
| Date | Duration | Customers affected | Cause |
|---|---|---|---|
| Mar 19, 2025 | 31 hrs | 2,838 (46%) | Hail |
| May 24, 2024 | 18 hrs | 2,439 (40%) | Hail |
| Jul 27, 2016 | 2 hrs | 2,406 (39%) | Excessive Heat |
| Dec 10, 2021 | 18 hrs | 2,353 (38%) | Winter Storm |
| Dec 16, 2021 | 30 hrs | 2,249 (37%) | Winter Storm |
Over the 11 years from 2015 to 2025, Calhoun County recorded 287 distinct power outage events, averaging 2.4 hours per event.
The single worst outage on record in Calhoun County started March 19, 2025 (Hail), lasting 31 hours and leaving up to 2,838 customers without power (46% of the county) at its peak.
July has historically been the worst month for outages in Calhoun County, with 37 events recorded during that month across the dataset.
Based on this history, Calhoun County earns a Reliability Grade of C, placing it in the 47th percentile nationally for grid reliability (higher percentile = more reliable).
Sized for Calhoun County's outage profile
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Similar counties in Iowa
Counties with the closest reliability grade and national percentile to Calhoun County.
| County | Grade | National percentile |
|---|---|---|
| Washington County | C | 47th |
| Grundy County | C | 46th |
| Appanoose County | C | 48th |
| Hancock County | C | 48th |
| Jones County | C | 45th |
Most reliable counties in Iowa
The top 3 counties in Iowa by reliability grade and percentile.
| County | Grade | National percentile |
|---|---|---|
| Clay County | A | 97th |
| Emmet County | A | 95th |
| Bremer County | A | 94th |
Least reliable counties in Iowa
The bottom 3 counties in Iowa by reliability grade and percentile.
| County | Grade | National percentile |
|---|---|---|
| Marshall County | F | 6th |
| Tama County | F | 12th |
| Jasper County | F | 14th |
Most reliable counties nationally
The top 3 counties nationally by reliability grade and percentile.
| County | State | Grade | National percentile |
|---|---|---|---|
| Clay County | South Dakota | A | 100th |
| Clearwater County | Minnesota | A | 99th |
| Limestone County | Alabama | A | 99th |
Least reliable counties nationally
The bottom 3 counties nationally by reliability grade and percentile.
| County | State | Grade | National percentile |
|---|---|---|---|
| Clay County | West Virginia | F | 0th |
| Lincoln County | West Virginia | F | 0th |
| Cameron Parish | Louisiana | F | 0th |
FAQ
How often does power go out in Calhoun County?
Between 2015 and 2025, Calhoun County recorded 287 outage events, averaging 2.4 hours each.
What is Calhoun County's reliability grade?
Calhoun County has a Reliability Grade of C, in the 47th national percentile.
What was the worst power outage in Calhoun County?
The worst outage on record started March 19, 2025 (Hail), lasting 31 hours and affecting up to 2,838 customers.