Mono CountyPower Outage History
2014–2025 · California
Bottom 20% least reliable nationally — frequent and/or long outages.
Outages by year
Outages by month (seasonality)
Worst outage events on record
| Date | Duration | Customers affected | Cause |
|---|---|---|---|
| Dec 13, 2015 | 5 hrs | 3,573 (64%) | Unnamed event |
| Jul 1, 2018 | <1 hr | 2,893 (52%) | Unnamed event |
| Feb 16, 2017 | 10 hrs | 2,665 (48%) | Heavy Snow |
| Sep 19, 2024 | 9 hrs | 2,356 (42%) | Heavy Rain |
| Aug 29, 2018 | 9 hrs | 2,212 (40%) | Unnamed event |
Over the 12 years from 2014 to 2025, Mono County recorded 1,442 distinct power outage events, averaging 5.2 hours per event.
The single worst outage on record in Mono County started December 13, 2015, lasting 5 hours and leaving up to 3,573 customers without power (64% of the county) at its peak.
June has historically been the worst month for outages in Mono County, with 194 events recorded during that month across the dataset.
Based on this history, Mono County earns a Reliability Grade of F, placing it in the 19th 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 Mono County.
| County | Grade | National percentile |
|---|---|---|
| Siskiyou County | F | 20th |
| Inyo County | F | 16th |
| Marin County | F | 16th |
| Yuba County | F | 15th |
| Sonoma County | F | 13th |
Most reliable counties in California
The top 3 counties in California by reliability grade and percentile.
| County | Grade | National percentile |
|---|---|---|
| Stanislaus County | A | 97th |
| Lassen County | A | 96th |
| San Benito County | B | 80th |
Least reliable counties in California
The bottom 3 counties in California by reliability grade and percentile.
| County | Grade | National percentile |
|---|---|---|
| Sierra County | F | 0th |
| Plumas County | F | 1st |
| Mariposa County | F | 1st |
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 Mono County?
Between 2014 and 2025, Mono County recorded 1,442 outage events, averaging 5.2 hours each.
What is Mono County's reliability grade?
Mono County has a Reliability Grade of F, in the 19th national percentile.
What was the worst power outage in Mono County?
The worst outage on record started December 13, 2015, lasting 5 hours and affecting up to 3,573 customers.