PowerOutageHistory
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Maricopa County Power Outage History

2015–2025 · Arizona

Top 20% most reliable nationally — infrequent, short outages. How grades are calculated

Total events
8,877
Avg duration
1.9 hrs
Longest outage
73 hrs
National percentile
86th

Outages by year

Outages by month (seasonality)

Worst outage events on record

DateDurationCustomers affectedCause
Jul 9, 201810 hrs109,160 (6%)Heat
Oct 3, 202222 hrs91,239 (5%)Heat
Sep 1, 202323 hrs83,324 (5%)Excessive Heat
Aug 17, 202125 hrs72,380 (4%)Dust Storm
Aug 9, 201819 hrs63,297 (3%)Heat

Over the 11 years from 2015 to 2025, Maricopa County recorded 8,877 distinct power outage events, averaging 1.9 hours per event.

The single worst outage on record in Maricopa County started July 9, 2018 (Heat), lasting 10 hours and leaving up to 109,160 customers without power (6% of the county) at its peak.

June has historically been the worst month for outages in Maricopa County, with 932 events recorded during that month across the dataset.

Based on this history, Maricopa County earns a Reliability Grade of A, placing it in the 86th percentile nationally for grid reliability (higher percentile = more reliable).

Sized for Maricopa County's outage profile

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Similar counties in Arizona

Counties with the closest reliability grade and national percentile to Maricopa County.

CountyGradeNational percentile
Pima CountyA86th
Coconino CountyA86th
Apache CountyA87th
Yavapai CountyA88th
Greenlee CountyA89th

FAQ

How often does power go out in Maricopa County?

Between 2015 and 2025, Maricopa County recorded 8,877 outage events, averaging 1.9 hours each.

What is Maricopa County's reliability grade?

Maricopa County has a Reliability Grade of A, in the 86th national percentile.

What was the worst power outage in Maricopa County?

The worst outage on record started July 9, 2018 (Heat), lasting 10 hours and affecting up to 109,160 customers.

Data: ORNL EAGLE-I Recorded Electricity Outages (2014–2025), CC BY 4.0. Storm names: NOAA Storm Events Database. Last data refresh: 2025. See methodology.