McHenry County Power Outage History
2014–2025 · Illinois
Better than average — fewer or shorter outages than most counties. How grades are calculated
Outages by year
Outages by month (seasonality)
Worst outage events on record
| Date | Duration | Customers affected | Cause |
|---|---|---|---|
| Feb 22, 2023 | 72 hrs | 36,109 (25%) | Winter Weather |
| Aug 11, 2021 | 34 hrs | 30,959 (21%) | Drought |
| Sep 25, 2018 | 29 hrs | 24,431 (17%) | Thunderstorm Wind |
| Aug 10, 2020 | 13 hrs | 18,037 (12%) | Tornado |
| Jun 8, 2015 | 0 hrs | 16,151 (11%) | Hail |
Over the 12 years from 2014 to 2025, McHenry County recorded 982 distinct power outage events, averaging 2.4 hours per event.
The single worst outage on record in McHenry County started February 22, 2023 (Winter Weather), lasting 72 hours and leaving up to 36,109 customers without power (25% of the county) at its peak.
July has historically been the worst month for outages in McHenry County, with 130 events recorded during that month across the dataset.
Based on this history, McHenry County earns a Reliability Grade of B, placing it in the 67th percentile nationally for grid reliability (higher percentile = more reliable).
Sized for McHenry County's outage profile
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Similar counties in Illinois
Counties with the closest reliability grade and national percentile to McHenry County.
| County | Grade | National percentile |
|---|---|---|
| Pike County | B | 67th |
| Kankakee County | B | 66th |
| Cumberland County | B | 65th |
| Clinton County | B | 68th |
| Madison County | B | 65th |
FAQ
How often does power go out in McHenry County?
Between 2014 and 2025, McHenry County recorded 982 outage events, averaging 2.4 hours each.
What is McHenry County's reliability grade?
McHenry County has a Reliability Grade of B, in the 67th national percentile.
What was the worst power outage in McHenry County?
The worst outage on record started February 22, 2023 (Winter Weather), lasting 72 hours and affecting up to 36,109 customers.