Jefferson CountyPower Outage History
What this grade means
Better than average — fewer or shorter outages than most counties. This county's outage history is better than the national median: recorded outages are less frequent and/or shorter in duration than a typical US county experienced over the same 12-year period. It isn't in the top tier nationally, but its track record points to lower-than-average outage risk.
Outages by year
Outages by month (seasonality)
Worst outage events on record
| Date | Duration | Customers affected | Cause |
|---|---|---|---|
| Aug 7, 2023 | 16 hrs | 11,865 (30%) | Thunderstorm Wind |
| Nov 29, 2023 | 8 hrs | 9,721 (25%) | Unnamed event |
| Sep 27, 2024 | 4 hrs | 9,007 (23%) | Tropical Storm Helene |
| Dec 23, 2022 | 2 hrs | 8,634 (22%) | Winter Storm Elliott |
| Apr 1, 2023 | 23 hrs | 8,009 (20%) | Unnamed event |
Was There an Outage on a Specific Date?
Pick a date to see whether a power outage was recorded for Jefferson County, Tennessee that day.
Over the 11 years from 2015 to 2025, Jefferson County recorded 369 distinct power outage events, averaging 2.4 hours per event.
The single worst outage on record in Jefferson County started August 7, 2023 (Thunderstorm Wind), lasting 16 hours and leaving up to 11,865 customers without power (30% of the county) at its peak.
June has historically been the worst month for outages in Jefferson County, with 54 events recorded during that month across the dataset.
Based on this history, Jefferson County earns a Reliability Grade of B, placing it in the 70th percentile nationally for grid reliability (higher percentile = more reliable).
Similar counties in Tennessee
Counties with the closest reliability grade and national percentile to Jefferson County.
| County | Grade | National percentile |
|---|---|---|
| Sequatchie County | B | 70th |
| Coffee County | B | 69th |
| Loudon County | B | 69th |
| Maury County | B | 68th |
| Haywood County | B | 72nd |
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 Jefferson County?
Between 2015 and 2025, Jefferson County recorded 369 outage events, averaging 2.4 hours each.
What is Jefferson County's reliability grade?
Jefferson County has a Reliability Grade of B, in the 70th national percentile.
What was the worst power outage in Jefferson County?
The worst outage on record started August 7, 2023 (Thunderstorm Wind), lasting 16 hours and affecting up to 11,865 customers.