Power outages in Montana
In 2025, the average Montana customer had 4.8 hours (288.1 minutes) without power. That is about 0.5 hours above the US median of 4.3 hours (258.7 minutes) across 50 states compared.
Trend
Outage time has moved up and down since 2020. It fell to 2.0 hours in 2023, then rose again. The worst year was 2024 at 5.9 hours.
Utilities in 2025
Among 2025 utilities, NorthWestern Energy LLC - (MT) had the lowest SAIDI at 2.1 hours (125.3 minutes). Missoula Electric Coop, Inc had the highest at 22.2 hours (1,331.9 minutes).
| Utility | Customers | Hours / yr | Interruptions |
|---|---|---|---|
| Missoula Electric Coop, Inc | 17,426 | 22.2 | 2.4 |
| Flathead Electric Coop Inc | 79,942 | 14.8 | 2.3 |
| Montana-Dakota Utilities Co | 27,906 | 2.4 | 1.2 |
| NorthWestern Energy LLC - (MT) | 383,135 | 2.1 | 1.1 |
What this means for backup power
For everyday outages, enter 3.5 hours in the calculator, the average length of one interruption. To ride out a year like 2024, size for 5.9 hours, the total outage time for that year.
FAQ
How long does a typical power outage last in Montana?
One interruption lasts 3.5 hours on average. In 2025, customers had about 1.4 interruptions per year (1.358).
What does SAIDI mean?
SAIDI is the total time a customer is without power in a year. It is not the length of one outage. Montana's 2025 SAIDI was 4.8 hours.
How much backup power should I plan for?
For everyday outages, use 3.5 hours in the calculator. If you want cover for a bad year like 2024, plan for 5.9 hours, the total outage time that year.
Utility pages
Source: U.S. EIA Form 861 Reliability file. Data snapshot 2026-11-05.