– 0% of Middlesex out 0 customers out in Massachusetts

Power outage history

Middlesex County Massachusetts

5.5hours

without power for the average customer in a typical year, 2018–2025

5th most of 14 in Massachusetts 16% below the national median

Worst outage on record Mar 8, 2018 34% of customers out · 90% back in 2.3 days

Hours without power, average customer per year 5.5h / yr State average 5.7 h · national median 6.6 h

Major outages a year 0.3 Peaks over 10% of customers or 50,000 customers

Typical time to restore 90% 2.3days Median across major outages, from the peak

Longest single outage 3.3days Mar 7, 2018, over 1% of customers out

Outage hours on storm days 94% Share falling on days with a NOAA storm report here

Worst year 2018 16 hours without power, average customer

Electricity customers 434,426 ORNL customer model · 8 well-covered years

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 Middlesex's customers who were without power at that day's worst moment.

20152016201720182019202020212022202320242025

0%100% of customers out

Year by year

Hours in the dark, per customer

2018 was the worst well-recorded year, at 16 hours for the average customer. Hatched years have a thin record and are left out of the averages.

Middlesex, hours without power per customer

MiddlesexUS median countyMassachusetts average

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 7, 2018	Winter storm	148,898	34%	3.3 d	2.3 d	5.6M
Oct 29, 2017	Windstorm	66,566	15%	3.0 d	2.4 d	2.1M
Dec 18, 2023	Windstorm	85,579	20%	40 h	29 h	1.2M
Oct 17, 2019	Windstorm	29,508	7%	38 h	29 h	517k
Feb 5, 2016	Winter storm	32,359	7%	33 h	31 h	508k
Sep 8, 2023	Thunderstorms	30,603	7%	32 h	14 h	406k
Mar 2, 2018	Windstorm	25,165	6%	28 h	26 h	357k
Oct 7, 2020	Thunderstorms	31,359	7%	29 h	34 h	351k
Feb 25, 2019	Windstorm	20,451	5%	26 h	25 h	306k
Apr 13, 2020	Windstorm	25,258	6%	21 h	21 h	210k
Jan 7, 2024	Winter storm	16,414	4%	31 h	29 h	210k
Dec 19, 2025	No storm report	19,321	4%	23 h	27 h	181k
May 15, 2020	Thunderstorms	15,420	4%	19 h	25 h	180k
Mar 14, 2023	Winter storm	11,860	3%	27 h	29 h	176k
Aug 4, 2020	Hurricane Isaias	17,121	4%	21 h	20 h	169k
Mar 14, 2017	Winter storm	27,304	6%	11 h	11 h	148k
Mar 1, 2021	Windstorm	14,349	3%	14 h	17 h	130k
Dec 23, 2022	Windstorm	20,981	5%	9.8 h	13 h	115k
Aug 4, 2015	Thunderstorms	22,430	5%	11 h	8.2 h	114k
Jul 23, 2016	Thunderstorms	10,367	2%	12 h	14 h	86k
Feb 25, 2016	Thunderstorms	11,291	3%	9.0 h	12 h	66k
Oct 27, 2021	Tropical Storm Wanda	10,324	2%	11 h	6.0 h	64k
Aug 23, 2020	Thunderstorms	14,944	3%	7.8 h	19 h	62k
Jun 24, 2025	Heat	15,271	4%	4.8 h	14 h	54k
Dec 5, 2020	Winter storm	14,217	3%	6.0 h	6.2 h	52k
Dec 23, 2022	Windstorm	10,481	2%	9.0 h	19 h	46k
Mar 2, 2017	Windstorm	10,056	2%	5.8 h	10 h	41k
Aug 7, 2022	Thunderstorms	11,027	3%	3.8 h	7.8 h	35k
Sep 11, 2016	Thunderstorms	7,496	2%	5.2 h	8.2 h	32k
Aug 15, 2024	Thunderstorms	10,049	2%	3.8 h	8.0 h	27k

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 Middlesex from twelve hours before it began to its peak. Matching shows coincidence, not proof of cause.

Winter storm 54%
Windstorm 27%
Thunderstorms 10%
No storm on record 5.7%
Tropical storm 2.1%

Who keeps the lights on

Utilities serving Middlesex

As each utility reports to the Energy Information Administration for its whole Massachusetts territory, not this county alone. Outage minutes include major storm days.

Utility	Type	Outage min / yr	Excl. major storms	Outages / yr	Residential ¢/kWh	Customers
NSTAR Electric Company	Investor Owned	113	66	0.81	21.5	1.3M
Massachusetts Electric Co	Investor Owned	133	91	1.00	33.7	1.2M
Town of Wakefield	MA	–	–	–	16.5	79k
Town of Concord	MA	–	–	–	16.2	69k
Town of Belmont	MA	127	127	0.73	20.4	68k
Town of Groton	MA	52	52	0.56	–	44k
Town of Reading	Municipal	50	21	0.48	19.9	27k
Fitchburg Gas & Elec Light Co	Investor Owned	74	74	1.08	36.2	26k
Town of Hudson	Municipal	63	61	1.17	13.1	12k
Town of Littleton	Municipal	–	–	–	14.2	6.8k
Massachusetts Bay Trans Authority	Political Subdivision	–	–	–	–	–

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

Essex 8.0 h
Middlesex (this county) 5.5 h
Norfolk 4.9 h
Hillsborough, NH 4.6 h
Worcester 4.0 h
Suffolk 1.7 h

Across Massachusetts

Where it is darkest

Hours / yr64+

All Massachusetts counties →

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 434,426 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 →