Power outage history
San Mateo County California
8.6hours
without power for the average customer in a typical year, 2018–2025
31st most of 56 in California 1.3× 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 San Mateo's customers who were without power at that day's worst moment.
Year by year
Hours in the dark, per customer
2023 was the worst well-recorded year, at 23 hours for the average customer. Hatched years have a thin record and are left out of the averages.
San Mateo, 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 |
|---|---|---|---|---|---|---|
| Oct 26, 2019 | Wildfire | 56,555 | 17% | 2.6 d | 30 h | 2.1M |
| Feb 4, 2024 | Windstorm | 81,483 | 25% | 3.3 d | 2.1 d | 2.0M |
| Feb 21, 2023 | Windstorm | 62,792 | 19% | 2.6 d | 2.0 d | 1.8M |
| Mar 14, 2023 | Windstorm | 67,816 | 21% | 2.7 d | 2.1 d | 1.7M |
| Jan 4, 2023 | No storm report | 42,670 | 13% | 4.1 d | 25 h | 1.2M |
| Oct 24, 2021 | No storm report | 46,910 | 14% | 2.3 d | 33 h | 952k |
| Mar 21, 2023 | Windstorm | 45,982 | 14% | 2.3 d | 21 h | 928k |
| Dec 14, 2024 | Flooding | 32,063 | 10% | 31 h | 31 h | 246k |
| Dec 25, 2025 | Thunderstorms | 18,374 | 6% | 21 h | 29 h | 230k |
| Jun 21, 2022 | Heat | 15,014 | 5% | 21 h | 20 h | 147k |
| Oct 17, 2021 | No storm report | 18,276 | 6% | 23 h | 21 h | 144k |
| Oct 9, 2019 | No storm report | 14,976 | 5% | 9.2 h | 17 h | 130k |
| Jan 10, 2023 | Thunderstorms | 19,500 | 6% | 6.2 h | 16 h | 100k |
| Feb 4, 2025 | Windstorm | 14,562 | 4% | 18 h | 16 h | 97k |
| Oct 8, 2024 | No storm report | 12,151 | 4% | 8.8 h | 11 h | 93k |
| Aug 16, 2020 | Wildfire | 21,648 | 7% | 11 h | 2.2 h | 91k |
| Dec 24, 2025 | Thunderstorms | 9,982 | 3% | 19 h | 28 h | 86k |
| Jan 16, 2019 | Windstorm | 21,625 | 7% | 7.0 h | 10 h | 81k |
| Jan 19, 2021 | Windstorm | 9,487 | 3% | 15 h | 23 h | 80k |
| Oct 25, 2020 | Windstorm | 4,395 | 1% | 19 h | – | 68k |
| Feb 26, 2019 | Windstorm | 10,271 | 3% | 7.0 h | 5.8 h | 68k |
| Oct 10, 2019 | No storm report | 14,986 | 5% | 5.8 h | 17 h | 65k |
| Jan 9, 2023 | No storm report | 6,331 | 2% | 14 h | 14 h | 58k |
| Mar 1, 2023 | No storm report | 10,866 | 3% | 10 h | 9.5 h | 54k |
| Sep 7, 2020 | Wildfire | 8,670 | 3% | 9.0 h | 10 h | 53k |
| Feb 14, 2019 | Windstorm | 14,831 | 5% | 5.2 h | 8.2 h | 40k |
| Dec 15, 2021 | No storm report | 4,822 | 1% | 10 h | – | 32k |
| Mar 12, 2025 | No storm report | 15,094 | 5% | 5.5 h | 6.0 h | 30k |
| Feb 9, 2020 | Windstorm | 9,553 | 3% | 6.8 h | 7.5 h | 28k |
| Jan 10, 2023 | Thunderstorms | 6,729 | 2% | 5.8 h | 18 h | 28k |
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 San Mateo from twelve hours before it began to its peak. Matching shows coincidence, not proof of cause.
- Windstorm 50%
- No storm on record 27%
- Wildfire 16%
- Thunderstorms 3.3%
- Flooding 2.4%
- Heat 1.1%
Who keeps the lights on
Utilities serving San Mateo
As each utility reports to the Energy Information Administration for its whole California territory, not this county alone. Outage minutes include major storm days.
| Utility | Type | Outage min / yr | Excl. major storms | Outages / yr | Residential ¢/kWh | Customers |
|---|---|---|---|---|---|---|
| Pacific Gas & Electric Co. | Investor Owned | 273 | 208 | 1.63 | 37.5 | 5.1M |
| City & County of San Francisco | Municipal | – | – | – | 27.1 | 3.7k |
| WAPA-- Western Area Power Administration | Federal | – | – | – | – | – |
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
- Santa Cruz 24 h
- San Mateo (this county) 8.6 h
- Santa Clara 4.7 h
- San Francisco 2.7 h
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 328,408 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 →