Sonoma County Power Outage History
2018–2025 · California
Bottom 20% least reliable nationally — frequent and/or long outages. How grades are calculated
Outages by year
Outages by month (seasonality)
Worst outage events on record
| Date | Duration | Customers affected | Cause |
|---|---|---|---|
| Oct 27, 2019 | 2 hrs | 105,823 (49%) | Strong Wind |
| Oct 27, 2019 | 4 hrs | 103,718 (48%) | Strong Wind |
| Oct 27, 2019 | 2 hrs | 102,064 (48%) | Strong Wind |
| Oct 27, 2019 | 5 hrs | 99,629 (47%) | Strong Wind |
| Oct 28, 2019 | 7 hrs | 98,773 (46%) | Strong Wind |
Over the 8 years from 2018 to 2025, Sonoma County recorded 3,047 distinct power outage events, averaging 3.4 hours per event.
The single worst outage on record in Sonoma County started October 27, 2019 (Strong Wind), lasting 2 hours and leaving up to 105,823 customers without power (49% of the county) at its peak.
October has historically been the worst month for outages in Sonoma County, with 358 events recorded during that month across the dataset.
Based on this history, Sonoma County earns a Reliability Grade of F, placing it in the 13th percentile nationally for grid reliability (higher percentile = more reliable).
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Similar counties in California
Counties with the closest reliability grade and national percentile to Sonoma County.
| County | Grade | National percentile |
|---|---|---|
| Yuba County | F | 15th |
| Marin County | F | 16th |
| Inyo County | F | 16th |
| Shasta County | F | 9th |
| Mono County | F | 19th |
FAQ
How often does power go out in Sonoma County?
Between 2018 and 2025, Sonoma County recorded 3,047 outage events, averaging 3.4 hours each.
What is Sonoma County's reliability grade?
Sonoma County has a Reliability Grade of F, in the 13th national percentile.
What was the worst power outage in Sonoma County?
The worst outage on record started October 27, 2019 (Strong Wind), lasting 2 hours and affecting up to 105,823 customers.