Ontario 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 |
|---|---|---|---|
| Jul 10, 2018 | <1 hr | 47,792 (63%) | Unnamed event |
| Dec 10, 2020 | 1 hrs | 21,726 (29%) | Unnamed event |
| Dec 23, 2022 | 45 hrs | 8,873 (12%) | Winter Storm Elliott |
| May 25, 2017 | <1 hr | 8,620 (11%) | Hail |
| Jun 23, 2015 | <1 hr | 7,799 (10%) | Thunderstorm Wind |
Was There an Outage on a Specific Date?
Pick a date to see whether a power outage was recorded for Ontario County, New York that day.
Over the 12 years from 2014 to 2025, Ontario County recorded 921 distinct power outage events, averaging 2.4 hours per event.
The single worst outage on record in Ontario County started July 10, 2018, lasting less than 1 hour and leaving up to 47,792 customers without power (63% of the county) at its peak.
June has historically been the worst month for outages in Ontario County, with 129 events recorded during that month across the dataset.
Based on this history, Ontario County earns a Reliability Grade of B, placing it in the 71st percentile nationally for grid reliability (higher percentile = more reliable).
Similar counties in New York
Counties with the closest reliability grade and national percentile to Ontario County.
| County | Grade | National percentile |
|---|---|---|
| Onondaga County | B | 76th |
| Chautauqua County | B | 64th |
| Tompkins County | B | 61st |
| Livingston County | C | 60th |
| Erie County | C | 59th |
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 Ontario County?
Between 2014 and 2025, Ontario County recorded 921 outage events, averaging 2.4 hours each.
What is Ontario County's reliability grade?
Ontario County has a Reliability Grade of B, in the 71st national percentile.
What was the worst power outage in Ontario County?
The worst outage on record started July 10, 2018, lasting less than 1 hour and affecting up to 47,792 customers.