San Mateo County Power Outage History
2018–2025 · California
Worse than average — more frequent or longer outages than most counties. How grades are calculated
Outages by year
Outages by month (seasonality)
Worst outage events on record
| Date | Duration | Customers affected | Cause |
|---|---|---|---|
| Feb 4, 2024 | 120 hrs | 81,483 (25%) | High Wind |
| Mar 14, 2023 | 11 hrs | 67,816 (21%) | High Wind |
| Feb 21, 2023 | 46 hrs | 62,792 (19%) | Strong Wind |
| Oct 27, 2019 | 5 hrs | 56,555 (17%) | Wildfire |
| Oct 27, 2019 | 3 hrs | 56,196 (17%) | Wildfire |
Over the 8 years from 2018 to 2025, San Mateo County recorded 3,437 distinct power outage events, averaging 3.3 hours per event.
The single worst outage on record in San Mateo County started February 4, 2024 (High Wind), lasting 120 hours and leaving up to 81,483 customers without power (25% of the county) at its peak.
October has historically been the worst month for outages in San Mateo County, with 360 events recorded during that month across the dataset.
Based on this history, San Mateo County earns a Reliability Grade of D, placing it in the 32nd percentile nationally for grid reliability (higher percentile = more reliable).
Sized for San Mateo County's outage profile
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Similar counties in California
Counties with the closest reliability grade and national percentile to San Mateo County.
| County | Grade | National percentile |
|---|---|---|
| Glenn County | D | 32nd |
| Ventura County | D | 35th |
| Placer County | D | 29th |
| Colusa County | D | 28th |
| Monterey County | D | 27th |
FAQ
How often does power go out in San Mateo County?
Between 2018 and 2025, San Mateo County recorded 3,437 outage events, averaging 3.3 hours each.
What is San Mateo County's reliability grade?
San Mateo County has a Reliability Grade of D, in the 32nd national percentile.
What was the worst power outage in San Mateo County?
The worst outage on record started February 4, 2024 (High Wind), lasting 120 hours and affecting up to 81,483 customers.