Coos County Power Outage History
2014–2025 · New Hampshire
Worse than average — more frequent or longer 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 |
|---|---|---|---|
| Jun 4, 2021 | 1 hrs | 9,692 (40%) | Drought |
| Oct 30, 2017 | 127 hrs | 8,259 (34%) | Tropical Storm Philippe |
| Jun 23, 2015 | 5 hrs | 7,202 (29%) | Thunderstorm Wind |
| Mar 2, 2021 | 14 hrs | 7,004 (29%) | Unnamed event |
| Dec 23, 2022 | 78 hrs | 6,516 (27%) | Winter Storm |
Over the 12 years from 2014 to 2025, Coos County recorded 588 distinct power outage events, averaging 2.9 hours per event.
The single worst outage on record in Coos County started June 4, 2021 (Drought), lasting 1 hours and leaving up to 9,692 customers without power (40% of the county) at its peak.
November has historically been the worst month for outages in Coos County, with 82 events recorded during that month across the dataset.
Based on this history, Coos County earns a Reliability Grade of D, placing it in the 27th percentile nationally for grid reliability (higher percentile = more reliable).
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Similar counties in New Hampshire
Counties with the closest reliability grade and national percentile to Coos County.
| County | Grade | National percentile |
|---|---|---|
| Rockingham County | D | 27th |
| Grafton County | D | 26th |
| Merrimack County | D | 33rd |
| Hillsborough County | D | 33rd |
| Cheshire County | F | 18th |
FAQ
How often does power go out in Coos County?
Between 2014 and 2025, Coos County recorded 588 outage events, averaging 2.9 hours each.
What is Coos County's reliability grade?
Coos County has a Reliability Grade of D, in the 27th national percentile.
What was the worst power outage in Coos County?
The worst outage on record started June 4, 2021 (Drought), lasting 1 hours and affecting up to 9,692 customers.