Power Out Map
– 0% of Day out 0 customers out in South Dakota

Power outage history

Day County South Dakota

8.5hours

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

9th most of 32 in South Dakota 1.3× the national median

Worst outage on record Aug 5, 2023 10% of customers out · 90% back in 4.2 days
Hours without power, average customer per year 8.5h / yr State average 4.8 h · national median 6.6 h
Major outages a year 4.0 Peaks over 10% of customers or 50,000 customers
Typical time to restore 90% 2hours Median across major outages, from the peak
Longest single outage 5.8days Aug 3, 2023, over 1% of customers out
Outage hours on storm days 21% Share falling on days with a NOAA storm report here
Worst year 2023 29 hours without power, average customer
Electricity customers 4,051 ORNL customer model · 7 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 Day'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

2023 was the worst well-recorded year, at 29 hours for the average customer. Hatched years have a thin record and are left out of the averages.

Day, hours without power per customer

DayUS median countySouth Dakota average
0 10 20 30 40 2.6 ’19 2.3 ’20 2.9 ’21 11 ’22 29 ’23 5.7 ’24 5.4 ’25 US 6.6 SD 4.8

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
Aug 3, 2023 No storm report 410 10% 5.8 d 4.2 d 44k
Jun 30, 2023 No storm report 284 7% 5.1 d 5.3 d 33k
Dec 13, 2022 Ice storm 2,317 57% 32 h 1.5 h 12k
Jul 4, 2022 No storm report 993 25% 25 h 11 h 11k
Mar 31, 2023 Winter storm 1,027 25% 16 h 15 h 10k
Dec 29, 2019 Winter storm 589 15% 14 h 14 h 8.1k
Jun 7, 2024 No storm report 496 12% 10 h 1.2 h 4.9k
Jul 28, 2023 No storm report 316 8% 2.3 d 35 h 4.6k
Aug 22, 2024 No storm report 253 6% 18 h 18 h 4.5k
Dec 27, 2022 No storm report 195 5% 26 h – 3.5k
Apr 6, 2022 Windstorm 2,407 59% 3.0 h 2.5 h 3.5k
May 31, 2025 No storm report 1,284 32% 2.8 h 2.5 h 3.5k

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.

0% 25% 50% 75% 100% peak+24h+48h+72h+96h half back by +6h 90% by +12h

When it happens

The outage clock

Customer-hours out by month (rings, January innermost) and local hour, 2018–2025.

00061218 Jan inside

What was happening

Weather behind the outages

Each outage is matched to NOAA storm reports for Day from twelve hours before it began to its peak. Matching shows coincidence, not proof of cause.

  • No storm on record 79%
  • Winter storm 10%
  • Ice storm 5.6%
  • Windstorm 2.9%
  • Thunderstorms 2.1%

Who keeps the lights on

Utilities serving Day

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

Utility Type Outage min / yr Excl. major storms Outages / yr Residential ¢/kWh Customers
Codington-Clark Elec Coop, Inc SD – – – 9.4 87k
Lake Region Electric Assn, Inc SD – – – 12.0 62k
NorthWestern Energy Investor Owned 120 82 1.14 13.3 52k
Otter Tail Power Co Investor Owned 191 189 1.73 11.4 9.1k
Montana-Dakota Utilities Co Investor Owned 212 206 2.62 13.0 6.3k
Northern Electric Coop, Inc Cooperative 73 65 0.74 11.4 5.8k
WAPA-- Western Area Power Administration Federal – – – – –

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

Across South Dakota

Where it is darkest

Hours / yr64+

All South Dakota 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 4,051 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 →