Jefferson CountyPower Outage History
What this grade means
Average — typical outage frequency and duration nationally. This county sits in the middle of the national distribution — its outage frequency and duration over the past 12 years are close to the nationwide median, neither notably better nor worse than most other US counties. A typical amount of backup-power preparedness is reasonable here.
Outages by year
Outages by month (seasonality)
Worst outage events on record
| Date | Duration | Customers affected | Cause |
|---|---|---|---|
| Feb 16, 2021 | 5 hrs | 12,259 (54%) | Winter Weather |
| Jul 5, 2021 | 1 hrs | 6,853 (30%) | Unnamed event |
| Feb 14, 2018 | 2 hrs | 6,191 (27%) | Winter Weather |
| Aug 20, 2018 | 3 hrs | 6,056 (27%) | Unnamed event |
| Jun 29, 2018 | 15 hrs | 5,485 (24%) | Thunderstorm Wind |
Was There an Outage on a Specific Date?
Pick a date to see whether a power outage was recorded for Jefferson County, Illinois that day.
Over the 12 years from 2014 to 2025, Jefferson County recorded 579 distinct power outage events, averaging 2.7 hours per event.
The single worst outage on record in Jefferson County started February 16, 2021 (Winter Weather), lasting 5 hours and leaving up to 12,259 customers without power (54% of the county) at its peak.
June has historically been the worst month for outages in Jefferson County, with 70 events recorded during that month across the dataset.
Based on this history, Jefferson County earns a Reliability Grade of C, placing it in the 47th percentile nationally for grid reliability (higher percentile = more reliable).
Similar counties in Illinois
Counties with the closest reliability grade and national percentile to Jefferson County.
| County | Grade | National percentile |
|---|---|---|
| Douglas County | C | 48th |
| Christian County | C | 48th |
| Shelby County | C | 46th |
| Lee County | C | 46th |
| Vermilion County | C | 46th |
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 2014 and 2025, Jefferson County recorded 579 outage events, averaging 2.7 hours each.
What is Jefferson County's reliability grade?
Jefferson County has a Reliability Grade of C, in the 47th national percentile.
What was the worst power outage in Jefferson County?
The worst outage on record started February 16, 2021 (Winter Weather), lasting 5 hours and affecting up to 12,259 customers.