Sweet Grass CountyPower Outage History
2020–2025 · Montana
Average — typical outage frequency and duration nationally. This county sits in the middle of the national distribution — its outage frequency and duration over the past 12 years are close to the nationwide median, neither notably better nor worse than most other US counties. A typical amount of backup-power preparedness is reasonable here.
Outages by year
Outages by month (seasonality)
Worst outage events on record
| Date | Duration | Customers affected | Cause |
|---|---|---|---|
| Dec 17, 2025 | 24 hrs | 1,612 (74%) | Winter Storm |
| Oct 26, 2021 | 5 hrs | 1,314 (61%) | High Wind |
| Dec 17, 2025 | <1 hr | 1,302 (60%) | Winter Storm |
| Dec 9, 2025 | 18 hrs | 817 (38%) | Winter Storm |
| Mar 9, 2021 | 2 hrs | 608 (28%) | Unnamed event |
Over the 6 years from 2020 to 2025, Sweet Grass County recorded 171 distinct power outage events, averaging 4.0 hours per event.
The single worst outage on record in Sweet Grass County started December 17, 2025 (Winter Storm), lasting 24 hours and leaving up to 1,612 customers without power (74% of the county) at its peak.
September has historically been the worst month for outages in Sweet Grass County, with 24 events recorded during that month across the dataset.
Based on this history, Sweet Grass County earns a Reliability Grade of C, placing it in the 54th percentile nationally for grid reliability (higher percentile = more reliable).
Sized for Sweet Grass County's outage profile
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Read our mission →Similar counties in Montana
Counties with the closest reliability grade and national percentile to Sweet Grass County.
| County | Grade | National percentile |
|---|---|---|
| Powell County | C | 55th |
| Golden Valley County | C | 58th |
| Judith Basin County | C | 49th |
| Valley County | C | 49th |
| Wheatland County | C | 48th |
Most reliable counties in Montana
The top 3 counties in Montana by reliability grade and percentile.
| County | Grade | National percentile |
|---|---|---|
| Powder River County | A | 95th |
| Roosevelt County | A | 94th |
| Fallon County | A | 94th |
Least reliable counties in Montana
The bottom 3 counties in Montana by reliability grade and percentile.
| County | Grade | National percentile |
|---|---|---|
| Lincoln County | F | 14th |
| Sanders County | D | 20th |
| Madison County | D | 31st |
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 Sweet Grass County?
Between 2020 and 2025, Sweet Grass County recorded 171 outage events, averaging 4.0 hours each.
What is Sweet Grass County's reliability grade?
Sweet Grass County has a Reliability Grade of C, in the 54th national percentile.
What was the worst power outage in Sweet Grass County?
The worst outage on record started December 17, 2025 (Winter Storm), lasting 24 hours and affecting up to 1,612 customers.