Power outage history
Waukesha County Wisconsin
6.9hours
without power for the average customer in a typical year, 2018–2025
13th most of 72 in Wisconsin close to the national median
Every day since 2015
Eleven years, one night at a time
Each cell is a day. The brighter it is, the larger the share of Waukesha's customers who were without power at that day's worst moment.
Year by year
Hours in the dark, per customer
2024 was the worst well-recorded year, at 13 hours for the average customer. Hatched years have a thin record and are left out of the averages.
Waukesha, hours without power per customer
The record
The biggest outages since 2015
Ranked by customer-hours lost: customers out multiplied by how long they stayed out. Times are local.
| Began | Storm | Peak out | Share | Lasted | 90% restored | Customer-hours |
|---|---|---|---|---|---|---|
| Jan 12, 2024 | Winter storm | 34,927 | 24% | 3.3 d | 2.2 d | 1.2M |
| Aug 10, 2021 | Thunderstorms | 45,425 | 32% | 3.0 d | 2.2 d | 918k |
| Jul 28, 2023 | Thunderstorms | 23,527 | 16% | 46 h | 40 h | 451k |
| Jun 27, 2019 | Thunderstorms | 19,874 | 14% | 30 h | 25 h | 275k |
| Dec 15, 2021 | Windstorm | 18,027 | 13% | 35 h | 18 h | 271k |
| Nov 5, 2022 | Windstorm | 15,243 | 11% | 34 h | 30 h | 235k |
| Jun 25, 2023 | Windstorm | 17,105 | 12% | 33 h | 26 h | 221k |
| Aug 9, 2025 | Flooding | 11,890 | 8% | 37 h | 33 h | 216k |
| Jul 29, 2021 | Tornadoes | 15,378 | 11% | 19 h | 14 h | 158k |
| Jun 30, 2019 | Thunderstorms | 21,890 | 15% | 9.2 h | 6.8 h | 128k |
| Jul 2, 2019 | Thunderstorms | 11,593 | 8% | 15 h | 12 h | 96k |
| May 21, 2024 | Thunderstorms | 16,312 | 11% | 13 h | 9.2 h | 80k |
| Jun 13, 2022 | Thunderstorms | 6,121 | 4% | 23 h | 28 h | 70k |
| Aug 12, 2025 | Thunderstorms | 14,153 | 10% | 11 h | 8.5 h | 62k |
| Jun 9, 2020 | Tropical Storm Cristobal | 5,976 | 4% | 17 h | 8.0 h | 57k |
| Sep 11, 2022 | Flooding | 5,743 | 4% | 15 h | 6.0 h | 55k |
| Jun 5, 2016 | Thunderstorms | 7,655 | 5% | 12 h | 13 h | 54k |
| Aug 14, 2015 | Thunderstorms | 6,061 | 4% | 18 h | 29 h | 52k |
| Nov 10, 2020 | Thunderstorms | 9,727 | 7% | 9.8 h | 4.8 h | 50k |
| Mar 10, 2023 | Winter storm | 8,655 | 6% | 15 h | 14 h | 50k |
| Jul 23, 2022 | No storm report | 5,621 | 4% | 15 h | 13 h | 42k |
| Jun 16, 2022 | Flooding | 5,371 | 4% | 8.8 h | 5.0 h | 42k |
| Mar 5, 2022 | No storm report | 6,013 | 4% | 9.8 h | 7.0 h | 40k |
| Oct 31, 2024 | No storm report | 5,444 | 4% | 13 h | 22 h | 37k |
| Jun 22, 2015 | Thunderstorms | 6,612 | 5% | 8.0 h | 10 h | 33k |
| Apr 20, 2017 | Thunderstorms | 6,281 | 4% | 8.2 h | 10 h | 33k |
| Jan 25, 2020 | Winter storm | 9,148 | 6% | 6.2 h | 5.0 h | 31k |
| Nov 24, 2018 | No storm report | 5,504 | 4% | 6.5 h | 5.8 h | 29k |
| Jan 9, 2024 | Winter storm | 7,928 | 6% | 5.8 h | 3.8 h | 27k |
| Nov 26, 2025 | No storm report | 6,104 | 4% | 10 h | 8.2 h | 26k |
After the peak
How fast the lights come back
Each line is one major outage, from its peak. The amber line is the typical path.
When it happens
The outage clock
Customer-hours out by month (rings, January innermost) and local hour, 2018–2025.
What was happening
Weather behind the outages
Each outage is matched to NOAA storm reports for Waukesha from twelve hours before it began to its peak. Matching shows coincidence, not proof of cause.
- Thunderstorms 39%
- Winter storm 22%
- No storm on record 17%
- Windstorm 12%
- Flooding 5.8%
- Tornadoes 2.8%
- Tropical storm 0.9%
Who keeps the lights on
Utilities serving Waukesha
As each utility reports to the Energy Information Administration for its whole Wisconsin territory, not this county alone. Outage minutes include major storm days.
| Utility | Type | Outage min / yr | Excl. major storms | Outages / yr | Residential ¢/kWh | Customers |
|---|---|---|---|---|---|---|
| Wisconsin Electric Power Co | Investor Owned | 185 | 93 | 0.90 | 20.5 | 1.1M |
| Oconomowoc Utilities | Municipal | 11 | 0 | 0.17 | 14.2 | 10k |
EIA Form 861, latest year each utility reported. Outage minutes are SAIDI, the yearly minutes the average customer goes without power; outages a year are SAIFI.
Next door
Neighbouring counties
About these numbers
Notes
Outages come from the EAGLE-I record of utility outage maps collected every 15 minutes by Oak Ridge National Laboratory. Hours without power are customer-hours divided by the county's 143,177 electricity customers. Averages use well-covered years from 2018. Outages shorter than 15 minutes, and utilities that publish no outage map, are not in the record, so these figures understate the total. How every number is made →