Coos CountyPower Outage History
What this grade means
Worse than average — more frequent or longer outages than most counties. This county's recorded history shows more frequent outages and/or longer restoration times than most US counties over the same 12-year period. If you live here, it's worth taking backup power more seriously than an average household would.
Outages by year
Outages by month (seasonality)
Worst outage events on record
| Date | Duration | Customers affected | Cause |
|---|---|---|---|
| Jun 4, 2021 | <1 hr | 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 |
Was There an Outage on a Specific Date?
Pick a date to see whether a power outage was recorded for Coos County, New Hampshire that day.
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 less than 1 hour 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).
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 |
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 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 less than 1 hour and affecting up to 9,692 customers.