Tuolumne 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 10, 2019 | 1 hrs | 37,533 (99%) | Strong Wind |
| Sep 9, 2023 | 54 hrs | 37,050 (98%) | Wildfire |
| Aug 26, 2021 | 29 hrs | 37,001 (98%) | Drought |
| Oct 10, 2019 | 1 hrs | 36,209 (96%) | Strong Wind |
| Oct 9, 2019 | 2 hrs | 35,846 (95%) | Strong Wind |
Over the 8 years from 2018 to 2025, Tuolumne County recorded 1,118 distinct power outage events, averaging 4.3 hours per event.
The single worst outage on record in Tuolumne County started October 10, 2019 (Strong Wind), lasting 1 hours and leaving up to 37,533 customers without power (99% of the county) at its peak.
October has historically been the worst month for outages in Tuolumne County, with 144 events recorded during that month across the dataset.
Based on this history, Tuolumne County earns a Reliability Grade of F, placing it in the 1st percentile nationally for grid reliability (higher percentile = more reliable).
Sized for Tuolumne County's outage profile
See more picks in our Best Dual-Fuel Portable Generators for Power Outages roundup.
Champion Power Equipment 4375-Watt Dual Fuel RV Ready Portable Generator with Free 3-Year Warranty
Outage-prep kit
See our outage-prep guides.
Similar counties in California
Counties with the closest reliability grade and national percentile to Tuolumne County.
| County | Grade | National percentile |
|---|---|---|
| Amador County | F | 1st |
| Butte County | F | 1st |
| Calaveras County | F | 1st |
| Mariposa County | F | 1st |
| Plumas County | F | 1st |
FAQ
How often does power go out in Tuolumne County?
Between 2018 and 2025, Tuolumne County recorded 1,118 outage events, averaging 4.3 hours each.
What is Tuolumne County's reliability grade?
Tuolumne County has a Reliability Grade of F, in the 1st national percentile.
What was the worst power outage in Tuolumne County?
The worst outage on record started October 10, 2019 (Strong Wind), lasting 1 hours and affecting up to 37,533 customers.