Sonoma CountyPower Outage History
What this grade means
Bottom 20% least reliable nationally — frequent and/or long outages. This county ranks in the least reliable fifth of all US counties in our dataset: some combination of frequent outages, long restoration times, or customers affected puts it near the bottom nationally. Backup power is worth prioritizing here rather than treating it as optional.
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 |
Was There an Outage on a Specific Date?
Pick a date to see whether a power outage was recorded for Sonoma County, California that day.
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).
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 |
Most reliable counties nationally
The top 3 counties nationally by reliability grade and percentile.
| County | State | Grade | National percentile |
|---|---|---|---|
| Clay County | South Dakota | A | 100th |
| Clearwater County | Minnesota | A | 99th |
| Limestone County | Alabama | A | 99th |
Least reliable counties nationally
The bottom 3 counties nationally by reliability grade and percentile.
| County | State | Grade | National percentile |
|---|---|---|---|
| Clay County | West Virginia | F | 0th |
| Lincoln County | West Virginia | F | 0th |
| Cameron Parish | Louisiana | F | 0th |
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.