Power outage history
Maricopa County Arizona
1.5hours
without power for the average customer in a typical year, 2018–2025
7th most of 11 in Arizona 77% below 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 Maricopa's customers who were without power at that day's worst moment.
Year by year
Hours in the dark, per customer
2018 was the worst well-recorded year, at 2.0 hours for the average customer. Hatched years have a thin record and are left out of the averages.
Maricopa, 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 |
|---|---|---|---|---|---|---|
| Jul 9, 2018 | Thunderstorms | 79,537 | 5% | 12 h | 10 h | 348k |
| Jul 8, 2018 | Heat | 42,517 | 2% | 10 h | 12 min | 261k |
| Aug 16, 2021 | Thunderstorms | 64,694 | 4% | 8.0 h | 9.0 h | 255k |
| Jul 17, 2022 | Thunderstorms | 48,316 | 3% | 7.8 h | 12 h | 234k |
| Sep 12, 2023 | Thunderstorms | 43,095 | 2% | 6.5 h | 9.0 h | 180k |
| Jul 30, 2018 | Thunderstorms | 38,908 | 2% | 4.8 h | 11 h | 154k |
| Jul 10, 2021 | Thunderstorms | 28,423 | 2% | 5.0 h | 8.2 h | 125k |
| Aug 31, 2023 | Thunderstorms | 47,814 | 3% | 6.0 h | 13 h | 121k |
| Aug 12, 2018 | Thunderstorms | 36,806 | 2% | 4.0 h | 9.0 h | 107k |
| Oct 13, 2025 | Thunderstorms | 33,144 | 2% | 4.0 h | 9.5 h | 83k |
| Jul 24, 2024 | Thunderstorms | 33,772 | 2% | 3.2 h | 12 h | 79k |
| Oct 3, 2022 | Windstorm | 51,570 | 3% | 2.0 h | 6.0 h | 68k |
| Jul 22, 2021 | Thunderstorms | 23,617 | 1% | 3.0 h | 14 h | 66k |
| Aug 20, 2020 | Heat | 36,749 | 2% | 2.5 h | 6.5 h | 63k |
| Jul 16, 2017 | Thunderstorms | 25,680 | 1% | 2.8 h | 7.2 h | 60k |
| Aug 31, 2015 | Thunderstorms | 20,854 | 1% | 3.0 h | 14 h | 59k |
| Aug 8, 2018 | Thunderstorms | 28,709 | 2% | 2.2 h | 5.5 h | 53k |
| Aug 3, 2017 | Thunderstorms | 25,572 | 1% | 1.8 h | 9.2 h | 31k |
| Aug 21, 2025 | Thunderstorms | 21,519 | 1% | 1.2 h | 2.2 h | 24k |
| Oct 18, 2015 | Thunderstorms | 21,506 | 1% | 1.0 h | 7.0 h | 20k |
| Jul 31, 2018 | Thunderstorms | 26,397 | 2% | 48 min | 3.5 h | 18k |
| Jun 16, 2018 | No storm report | 18,201 | 1% | 1.0 h | 2.2 h | 18k |
| Sep 1, 2015 | Thunderstorms | 17,918 | 1% | 2.2 h | 12 h | 18k |
| Jul 27, 2023 | Thunderstorms | 21,432 | 1% | 48 min | 2.8 h | 15k |
| Jan 25, 2021 | Thunderstorms | 21,145 | 1% | 48 min | 5.8 h | 15k |
| Aug 12, 2022 | Thunderstorms | 21,548 | 1% | 1.2 h | 4.8 h | 15k |
| Sep 11, 2022 | Thunderstorms | 19,731 | 1% | 48 min | 4.2 h | 14k |
| May 6, 2025 | Flooding | 19,365 | 1% | 30 min | 48 min | 9.7k |
| Oct 5, 2021 | Thunderstorms | 19,566 | 1% | 48 min | 1.8 h | 9.4k |
| Aug 10, 2018 | Flooding | 19,157 | 1% | 48 min | 12 min | 9.4k |
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 Maricopa from twelve hours before it began to its peak. Matching shows coincidence, not proof of cause.
- Thunderstorms 81%
- Heat 14%
- Windstorm 2.9%
- No storm on record 1.1%
- Flooding 0.8%
Who keeps the lights on
Utilities serving Maricopa
As each utility reports to the Energy Information Administration for its whole Arizona territory, not this county alone. Outage minutes include major storm days.
| Utility | Type | Outage min / yr | Excl. major storms | Outages / yr | Residential ¢/kWh | Customers |
|---|---|---|---|---|---|---|
| Arizona Public Service Co | Investor Owned | 73 | 73 | 0.84 | 17.0 | 1.3M |
| Salt River Project | Political Subdivision | 66 | 50 | 1.02 | 14.0 | 1.1M |
| Tohono O'Odham Utility Authority | AZ | – | – | – | – | 31k |
| City of Mesa | Municipal | 52 | 39 | 0.51 | 20.6 | 16k |
| USBIA-San Carlos Project | Federal | – | – | – | 16.4 | 12k |
| Town of Wickenburg | AZ | – | – | – | – | 11k |
| Gila River Indian Utility Authority (GRICUA) | Cooperative | 264 | 264 | 6.27 | 14.3 | 2.7k |
| Buckeye Water C&D District | AZ | – | – | – | – | 1.3k |
| Ocotillo Water Conserv. Dist. | AZ | – | – | – | – | 1.1k |
| WAPA-- Western Area Power Administration | Federal | – | – | – | – | – |
| Maricopa County M W C Dist #1 | AZ | – | – | – | – | – |
| Harquahala Valley Pwr District | AZ | – | – | – | – | – |
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.
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 1,742,493 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 →