Pennington County Power Outage History
2016–2025 · South Dakota
Top 20% most reliable nationally — infrequent, short outages. How grades are calculated
Outages by year
Outages by month (seasonality)
Worst outage events on record
| Date | Duration | Customers affected | Cause |
|---|---|---|---|
| Nov 13, 2025 | 7 hrs | 41,253 (44%) | Unnamed event |
| Dec 18, 2025 | 121 hrs | 25,159 (27%) | High Wind |
| Feb 11, 2016 | 1 hrs | 22,078 (24%) | High Wind |
| Aug 10, 2019 | 0 hrs | 7,770 (8%) | Thunderstorm Wind |
| Jan 24, 2019 | 1 hrs | 5,427 (6%) | Winter Storm |
Over the 10 years from 2016 to 2025, Pennington County recorded 435 distinct power outage events, averaging 3.4 hours per event.
The single worst outage on record in Pennington County started November 13, 2025, lasting 7 hours and leaving up to 41,253 customers without power (44% of the county) at its peak.
August has historically been the worst month for outages in Pennington County, with 48 events recorded during that month across the dataset.
Based on this history, Pennington County earns a Reliability Grade of A, placing it in the 81st percentile nationally for grid reliability (higher percentile = more reliable).
Sized for Pennington County's outage profile
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Similar counties in South Dakota
Counties with the closest reliability grade and national percentile to Pennington County.
| County | Grade | National percentile |
|---|---|---|
| Ziebach County | A | 81st |
| Jones County | A | 82nd |
| Lyman County | A | 81st |
| Brule County | B | 80th |
| Roberts County | A | 83rd |
FAQ
How often does power go out in Pennington County?
Between 2016 and 2025, Pennington County recorded 435 outage events, averaging 3.4 hours each.
What is Pennington County's reliability grade?
Pennington County has a Reliability Grade of A, in the 81st national percentile.
What was the worst power outage in Pennington County?
The worst outage on record started November 13, 2025, lasting 7 hours and affecting up to 41,253 customers.