New Haven County Power Outage History
2014–2025 · Connecticut
Average — typical outage frequency and duration nationally. How grades are calculated
Outages by year
Outages by month (seasonality)
Worst outage events on record
| Date | Duration | Customers affected | Cause |
|---|---|---|---|
| Aug 4, 2020 | 177 hrs | 140,925 (37%) | Hurricane Isaias |
| Aug 27, 2020 | 70 hrs | 50,268 (13%) | Unnamed event |
| May 15, 2018 | 155 hrs | 50,262 (13%) | Unnamed event |
| Mar 7, 2018 | 95 hrs | 38,525 (10%) | High Wind |
| Oct 30, 2017 | 52 hrs | 35,290 (9%) | Strong Wind |
Over the 12 years from 2014 to 2025, New Haven County recorded 2,394 distinct power outage events, averaging 2.1 hours per event.
The single worst outage on record in New Haven County started August 4, 2020 (Hurricane Isaias), lasting 177 hours and leaving up to 140,925 customers without power (37% of the county) at its peak.
July has historically been the worst month for outages in New Haven County, with 251 events recorded during that month across the dataset.
Based on this history, New Haven County earns a Reliability Grade of C, placing it in the 44th percentile nationally for grid reliability (higher percentile = more reliable).
Sized for New Haven County's outage profile
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Similar counties in Connecticut
Counties with the closest reliability grade and national percentile to New Haven County.
| County | Grade | National percentile |
|---|---|---|
| Hartford County | C | 58th |
| Tolland County | D | 26th |
| Middlesex County | D | 21st |
| Fairfield County | F | 19th |
| New London County | F | 19th |
FAQ
How often does power go out in New Haven County?
Between 2014 and 2025, New Haven County recorded 2,394 outage events, averaging 2.1 hours each.
What is New Haven County's reliability grade?
New Haven County has a Reliability Grade of C, in the 44th national percentile.
What was the worst power outage in New Haven County?
The worst outage on record started August 4, 2020 (Hurricane Isaias), lasting 177 hours and affecting up to 140,925 customers.