County annual report · FIPS 46037
2025 Day County, SD Power Outage Report
In 2025, customers in Day County, SD went without power for an average of 5.4 hours, a total of 22K customer-hours (South Dakota average 6.5 hours). That ranks 23rd worst of 65 South Dakota counties and 1407th of 3,000 nationally.
Compared with SD, the US and 2024
Coverage line is EAGLE-I's share of South Dakota customers tracked each year.
Biggest outages in Day County, 2025
The 10 outage episodes with the most customers out at once. Times are UTC.
| # | Started (UTC) | Ended (UTC) | Duration | Peak out | Customer-hours |
|---|---|---|---|---|---|
| 1 | November 25, 2025 17:30 | November 26, 2025 16:15 | 22h 45m | 1,447 | 2,727 |
| 2 | May 31, 2025 14:45 | May 31, 2025 17:30 | 2h 45m | 1,284 | 3,468 |
| 3 | February 23, 2025 18:15 | February 23, 2025 21:30 | 3h 15m | 1,008 | 1,980 |
| 4 | August 16, 2025 04:00 | August 16, 2025 18:15 | 14h 15m | 688 | 1,214 |
| 5 | December 18, 2025 09:30 | December 18, 2025 15:15 | 5h 45m | 448 | 700 |
| 6 | November 1, 2025 09:45 | November 1, 2025 10:45 | 1h | 437 | 437 |
| 7 | June 11, 2025 14:15 | June 12, 2025 01:00 | 10h 45m | 401 | 1,610 |
| 8 | April 14, 2025 22:15 | April 14, 2025 23:00 | 45m | 254 | 127 |
| 9 | October 5, 2025 23:00 | October 6, 2025 02:15 | 3h 15m | 246 | 800 |
| 10 | May 11, 2025 22:30 | May 12, 2025 07:00 | 8h 30m | 245 | 937 |
Outage episodes by size in 2025: 14 reached 100+ customers, 3 reached 1,000+ customers, 0 reached 10,000+ customers.
Utility reliability filed with the EIA
SAIDI (average outage time per customer) and SAIFI (average interruptions per customer) that utilities serving Day County reported on EIA Form 861 for 2025, or their most recent earlier filing. Utility-wide figures, not county-specific.
| Utility | EIA year | SAIDI | SAIFI | SAIDI excl. major events | SAIFI excl. major events |
|---|---|---|---|---|---|
| Otter Tail Power Co | 2024 | 2.6 hrs | 1.37 | 1.9 hrs | 1.09 |
| Montana-Dakota Utilities Co | 2024 | 2.9 hrs | 1.26 | 2.1 hrs | 1.10 |
| NorthWestern Energy - (SD) | 2024 | 76 min | 0.70 | 66 min | 0.65 |
| Northern Electric Coop, Inc | 2024 | 50 min | 0.67 | 50 min | 0.67 |
| WAPA-- Western Area Power Administration | - | - | - | - | - |
| Codington-Clark Elec Coop, Inc | - | - | - | - | - |
| Lake Region Electric Assn, Inc - (SD) | - | - | - | - | - |
About this data
- Outage figures come from DOE/ORNL EAGLE-I, which records customers out by county every 15 minutes. EAGLE-I tracked about n/a of South Dakota's customers in 2025; utilities it does not see are not counted.
- Hours per customer = outage customer-minutes ÷ 4,051 customers (ORNL modeled county customer count), including major storm days. It is comparable across counties but is not the SAIDI a utility files.
- An outage event is a continuous stretch with customers out; counts at 100, 1,000 and 10,000+ use its peak.
- Years loaded: 2015–2025. Day County has data for 2019–2025.
Cite this report
MassOutage (massoutage.com), Day County, SD annual power outage report, 2025, data as of Oct 3, 2026 02:41 UTC, sources: DOE EAGLE-I (https://eagle-i.doe.gov/); EAGLE-I modeled customer counts (MCC) (https://figshare.com/); EIA Form 861 (utility reliability) (https://www.eia.gov/electricity/data/eia861/). https://massoutage.com/reports/2025/south-dakota/day-county