King County Power Outage History
2014–2025 · Washington
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 |
|---|---|---|---|
| Nov 19, 2024 | 178 hrs | 518,386 (53%) | Unnamed event |
| Jan 12, 2021 | 109 hrs | 215,586 (22%) | Flood |
| Sep 11, 2024 | 4 hrs | 197,763 (20%) | Unnamed event |
| Nov 13, 2017 | 64 hrs | 132,417 (13%) | Unnamed event |
| Mar 13, 2016 | 12 hrs | 129,685 (13%) | Unnamed event |
Over the 12 years from 2014 to 2025, King County recorded 5,737 distinct power outage events, averaging 4.0 hours per event.
The single worst outage on record in King County started November 19, 2024, lasting 178 hours and leaving up to 518,386 customers without power (53% of the county) at its peak.
July has historically been the worst month for outages in King County, with 609 events recorded during that month across the dataset.
Based on this history, King County earns a Reliability Grade of D, placing it in the 28th percentile nationally for grid reliability (higher percentile = more reliable).
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Similar counties in Washington
Counties with the closest reliability grade and national percentile to King County.
| County | Grade | National percentile |
|---|---|---|
| Kittitas County | D | 31st |
| Garfield County | D | 32nd |
| Whatcom County | D | 24th |
| Lincoln County | D | 23rd |
| Thurston County | D | 33rd |
FAQ
How often does power go out in King County?
Between 2014 and 2025, King County recorded 5,737 outage events, averaging 4.0 hours each.
What is King County's reliability grade?
King County has a Reliability Grade of D, in the 28th national percentile.
What was the worst power outage in King County?
The worst outage on record started November 19, 2024, lasting 178 hours and affecting up to 518,386 customers.