County annual report · FIPS 55055
2021 Jefferson County, WI Power Outage Report
In 2021, customers in Jefferson County, WI went without power for an average of 5.7 hours, a total of 198K customer-hours (Wisconsin average 4.7 hours). That ranks 16th worst of 72 Wisconsin counties and 1195th of 2,974 nationally.
Compared with WI, the US and 2020
Coverage line is EAGLE-I's share of Wisconsin customers tracked each year.
Biggest outages in Jefferson County, 2021
The 10 outage episodes with the most customers out at once. Times are UTC.
| # | Started (UTC) | Ended (UTC) | Duration | Peak out | Customer-hours |
|---|---|---|---|---|---|
| 1 | July 29, 2021 06:00 | July 31, 2021 00:00 | 1d 18h | 6,941 | 69K |
| 2 | August 10, 2021 23:45 | August 11, 2021 12:45 | 13h | 4,232 | 16K |
| 3 | July 18, 2021 17:30 | July 18, 2021 19:45 | 2h 15m | 3,853 | 1,146 |
| 4 | December 16, 2021 00:30 | December 18, 2021 02:30 | 2d 2h | 3,752 | 50K |
| 5 | March 29, 2021 13:30 | March 29, 2021 16:15 | 2h 45m | 3,717 | 3,718 |
| 6 | August 7, 2021 17:45 | August 8, 2021 09:00 | 15h 15m | 2,690 | 7,975 |
| 7 | February 24, 2021 17:15 | February 24, 2021 22:30 | 5h 15m | 1,701 | 1,694 |
| 8 | October 25, 2021 05:15 | October 25, 2021 09:45 | 4h 30m | 1,659 | 4,560 |
| 9 | October 29, 2021 08:00 | October 29, 2021 09:00 | 1h | 1,622 | 451 |
| 10 | May 1, 2021 22:00 | May 2, 2021 00:30 | 2h 30m | 1,479 | 1,712 |
Outage episodes by size in 2021: 45 reached 100+ customers, 15 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 Jefferson County reported on EIA Form 861 for 2021, 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 |
|---|---|---|---|---|---|
| Wisconsin Electric Power Co | 2021 | 7.0 hrs | 1.13 | 1.7 hrs | 0.73 |
| Adams-Columbia Electric Coop | 2021 | 1.7 hrs | 0.74 | 1.7 hrs | 0.74 |
| Wisconsin Power & Light Co | - | - | - | - | - |
| Jefferson Utilities | - | - | - | - | - |
| Lake Mills Light & Water | - | - | - | - | - |
| Waterloo Light & Water Comm | - | - | - | - | - |
About this data
- Outage figures come from DOE/ORNL EAGLE-I, which records customers out by county every 15 minutes. EAGLE-I tracked about 85% of Wisconsin's customers in 2021; utilities it does not see are not counted.
- Hours per customer = outage customer-minutes ÷ 34,512 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. Jefferson County has data for 2015–2025.
Cite this report
MassOutage (massoutage.com), Jefferson County, WI annual power outage report, 2021, 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/2021/wisconsin/jefferson-county