Power outage history
Montgomery County Maryland
2.8hours
without power for the average customer in a typical year, 2018–2025
15th most of 24 in Maryland 58% below the national median
Every day since 2015
Eleven years, one night at a time
Each cell is a day. The brighter it is, the larger the share of Montgomery's customers who were without power at that day's worst moment.
Year by year
Hours in the dark, per customer
2018 was the worst well-recorded year, at 6.1 hours for the average customer. Hatched years have a thin record and are left out of the averages.
Montgomery, hours without power per customer
The record
The biggest outages since 2015
Ranked by customer-hours lost: customers out multiplied by how long they stayed out. Times are local.
| Began | Storm | Peak out | Share | Lasted | 90% restored | Customer-hours |
|---|---|---|---|---|---|---|
| Mar 2, 2018 | Windstorm | 108,677 | 27% | 2.7 d | 25 h | 1.9M |
| Jul 29, 2023 | Thunderstorms | 55,999 | 14% | 37 h | 33 h | 575k |
| Nov 27, 2022 | No storm report | 96,505 | 24% | 6.5 h | 1.2 h | 430k |
| Jun 19, 2025 | Thunderstorms | 29,030 | 7% | 16 h | 20 h | 250k |
| Jun 23, 2015 | Thunderstorms | 20,436 | 5% | 19 h | 19 h | 190k |
| Dec 23, 2022 | Winter storm | 19,429 | 5% | 16 h | 13 h | 167k |
| Jul 3, 2022 | Flooding | 27,552 | 7% | 10 h | 4.5 h | 158k |
| Jul 12, 2022 | Thunderstorms | 16,882 | 4% | 8.8 h | 8.8 h | 93k |
| Jul 15, 2024 | Thunderstorms | 15,801 | 4% | 6.2 h | 6.0 h | 60k |
| Aug 15, 2016 | Thunderstorms | 9,511 | 2% | 8.5 h | 8.8 h | 60k |
| Aug 11, 2021 | Thunderstorms | 11,763 | 3% | 7.8 h | 16 h | 58k |
| May 23, 2019 | Thunderstorms | 21,750 | 6% | 5.2 h | 6.8 h | 56k |
| May 16, 2025 | Thunderstorms | 14,073 | 4% | 6.5 h | 11 h | 55k |
| Feb 16, 2025 | Windstorm | 9,668 | 2% | 10 h | 21 h | 55k |
| Jul 28, 2023 | Thunderstorms | 10,475 | 3% | 5.5 h | 17 h | 41k |
| Jun 20, 2015 | No storm report | 6,723 | 2% | 7.2 h | 12 h | 40k |
| Aug 13, 2021 | Thunderstorms | 8,836 | 2% | 5.5 h | 4.0 h | 38k |
| Jun 21, 2016 | Thunderstorms | 10,308 | 3% | 7.0 h | 6.8 h | 38k |
| Jul 1, 2021 | Thunderstorms | 8,568 | 2% | 4.2 h | 7.0 h | 28k |
| Jul 24, 2022 | No storm report | 6,709 | 2% | 5.0 h | 5.2 h | 26k |
| Jun 19, 2015 | No storm report | 9,012 | 2% | 3.0 h | 3.2 h | 23k |
| Jul 26, 2021 | Thunderstorms | 6,352 | 2% | 4.5 h | 12 h | 22k |
| Apr 7, 2016 | No storm report | 9,729 | 2% | 2.5 h | 4.0 h | 20k |
| Jul 2, 2019 | Thunderstorms | 6,378 | 2% | 3.8 h | 9.8 h | 19k |
| Oct 31, 2019 | Flooding | 12,705 | 3% | 3.8 h | 1.5 h | 19k |
| Mar 6, 2018 | No storm report | 5,908 | 1% | 3.5 h | 6.0 h | 18k |
| Apr 30, 2021 | Thunderstorms | 6,301 | 2% | 3.2 h | 8.8 h | 17k |
| Nov 2, 2020 | No storm report | 4,811 | 1% | 3.2 h | – | 14k |
| May 24, 2022 | No storm report | 10,885 | 3% | 1.5 h | 12 min | 14k |
| Jun 16, 2022 | No storm report | 5,360 | 1% | 2.5 h | 1.0 h | 13k |
After the peak
How fast the lights come back
Each line is one major outage, from its peak. The amber line is the typical path.
When it happens
The outage clock
Customer-hours out by month (rings, January innermost) and local hour, 2018–2025.
What was happening
Weather behind the outages
Each outage is matched to NOAA storm reports for Montgomery from twelve hours before it began to its peak. Matching shows coincidence, not proof of cause.
- Windstorm 45%
- Thunderstorms 32%
- No storm on record 14%
- Winter storm 4.5%
- Flooding 4.1%
Who keeps the lights on
Utilities serving Montgomery
As each utility reports to the Energy Information Administration for its whole Maryland territory, not this county alone. Outage minutes include major storm days.
| Utility | Type | Outage min / yr | Excl. major storms | Outages / yr | Residential ¢/kWh | Customers |
|---|---|---|---|---|---|---|
| Baltimore Gas & Electric Co | Investor Owned | 175 | 65 | 0.87 | 20.2 | 1.2M |
| Potomac Electric Power Co | Investor Owned | 104 | 54 | 0.74 | 21.7 | 559k |
| The Potomac Edison Company | Investor Owned | 399 | 174 | 1.30 | 15.4 | 259k |
EIA Form 861, latest year each utility reported. Outage minutes are SAIDI, the yearly minutes the average customer goes without power; outages a year are SAIFI.
Next door
Neighbouring counties
- Arlington, VA 4.5 h
- Fairfax, VA 3.5 h
- Prince George's 3.2 h
- Montgomery (this county) 2.8 h
- Frederick 2.6 h
- Loudoun, VA 2.6 h
- Howard 2.3 h
- District of Columbia, DC 2.1 h
About these numbers
Notes
Outages come from the EAGLE-I record of utility outage maps collected every 15 minutes by Oak Ridge National Laboratory. Hours without power are customer-hours divided by the county's 395,748 electricity customers. Averages use well-covered years from 2018. Outages shorter than 15 minutes, and utilities that publish no outage map, are not in the record, so these figures understate the total. How every number is made →