San Mateo County, California Power Outages, 2018 to 2023

San Mateo County, California had 28 major outages from 2018 to 2023

Above middle outage time among US counties

Residents here averaged 1.36 times the US outage time per person and 1.52 times the California rate. It ranks 23 of 55 in the state, where 1 has the most. Data confidence: Medium, with 6 years of records.

4.7major outages per year

6 of 6years with a major outage

64 hrslongest major outage

Oct, Marhardest months

October and March made up 46% of this county's outage time. The largest outage on record began Feb 21, 2023, reached 62,792 customers, and left at least 200 customers out for 46.2 hours.

Outage time per resident, rated California counties

MostLeast

Outage impact by year

Customer-hours without power. 1,000 customers out for 2 hours is 2,000 customer-hours.

2018'182019'192020'202021'212022'222023'23

Show yearly numbers

Year	Customer-hours	Reported outages	Major outages
2018	310,586	160	1
2019	2,861,707	383	3
2020	1,093,104	456	2
2021	2,375,834	443	5
2022	955,153	442	3
2023	7,225,759	439	14

When outages hit

Share of this county's customer-hours by month.

10%

20%

30%

40%

JanJFebFMarMAprAMayMJunJJulJAugASepSOctONovNDecD

Largest outages on record

Start date	Hours	Peak customers	Customer-hours
Feb 21, 2023	46.2	62,792	1,590,429
Mar 15, 2023	40.5	51,381	1,184,854
Jan 4, 2023	45.2	42,670	913,150
Mar 21, 2023	23.0	45,982	589,615
Oct 25, 2021	20.8	30,897	451,082

Hours measure how long at least 200 customers in the county were out. Most customers get power back sooner.

Size your backup battery

Start with what you would keep running. Wattages are typical averages, so check your own appliances.

Phones, Wi-Fi, lights, about 60 WRefrigerator, about 60 WChest freezer, about 40 WGas furnace fan, about 160 W

Hours to cover: 24

1,700 Whof battery capacity, allowing for about 15% conversion loss

If anyone relies on medical equipment, plan that with their provider. Run portable fuel generators outdoors only, at least 20 feet from doors, windows and vents. See the outage checklist.

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How to read this

A major outage lasted at least 8 hours and reached customers equal to at least 1% of county residents.
Records cover outages of at least 200 customers in a county. They do not show what happened on your street.
Utilities that do not report can make a county look better than it is. Data ends in 2023. Read the full method.