Calvert 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 |
|---|---|---|---|
| Jan 3, 2022 | 76 hrs | 12,581 (18%) | Winter Storm |
| Aug 4, 2020 | 35 hrs | 11,675 (16%) | Tropical Storm Isaias |
| May 16, 2025 | 32 hrs | 8,498 (12%) | Thunderstorm Wind |
| Jul 7, 2020 | 7 hrs | 8,457 (12%) | Unnamed event |
| Sep 15, 2021 | 2 hrs | 8,069 (11%) | Unnamed event |
Was There an Outage on a Specific Date?
Pick a date to see whether a power outage was recorded for Calvert County, Maryland that day.
Over the 12 years from 2014 to 2025, Calvert County recorded 599 distinct power outage events, averaging 2.1 hours per event.
The single worst outage on record in Calvert County started January 3, 2022 (Winter Storm), lasting 76 hours and leaving up to 12,581 customers without power (18% of the county) at its peak.
July has historically been the worst month for outages in Calvert County, with 73 events recorded during that month across the dataset.
Based on this history, Calvert County earns a Reliability Grade of B, placing it in the 76th percentile nationally for grid reliability (higher percentile = more reliable).
Similar counties in Maryland
Counties with the closest reliability grade and national percentile to Calvert County.
| County | Grade | National percentile |
|---|---|---|
| Frederick County | B | 74th |
| Howard County | B | 78th |
| Somerset County | B | 74th |
| Caroline County | B | 79th |
| Queen Anne's County | B | 79th |
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 Calvert County?
Between 2014 and 2025, Calvert County recorded 599 outage events, averaging 2.1 hours each.
What is Calvert County's reliability grade?
Calvert County has a Reliability Grade of B, in the 76th national percentile.
What was the worst power outage in Calvert County?
The worst outage on record started January 3, 2022 (Winter Storm), lasting 76 hours and affecting up to 12,581 customers.