NorthWestern Energy Electricity Rates and Average Bill (South Dakota)
Data through August 2026 (the latest month EIA has published) · Updated October 31, 2026
As of August 2026, NorthWestern Energy's residential customers in South Dakota paid an average effective rate of 14.12¢/kWh with an average monthly bill of $162.35, per EIA Form 861-M data. That rate is 1.0¢ below the South Dakota average of 15.15¢/kWh; the U.S. average is 18.16¢/kWh.
Rate trend vs the South Dakota average
View this chart as a table (last 12 months)
| Month | Rate (¢/kWh) | Avg bill ($/mo) | Avg usage (kWh/mo) |
|---|---|---|---|
| September 2025 | 14.53 | 131.45 | 905 |
| October 2025 | 15.13 | 110.71 | 732 |
| November 2025 | 15.28 | 98.64 | 646 |
| December 2025 | 13.61 | 137.45 | 1010 |
| January 2026 | 12.89 | 157.65 | 1223 |
| February 2026 | 12.78 | 155.76 | 1219 |
| March 2026 | 13.60 | 133.16 | 979 |
| April 2026 | 14.26 | 121.99 | 856 |
| May 2026 | 15.31 | 104.37 | 682 |
| June 2026 | 15.25 | 119.53 | 784 |
| July 2026 | 14.81 | 136.53 | 922 |
| August 2026 | 14.12 | 162.35 | 1149 |
NorthWestern Energy vs South Dakota vs the U.S.
| NorthWestern Energy | South Dakota | U.S. average | |
|---|---|---|---|
| Rate (August 2026) | 14.12¢/kWh | 15.15¢/kWh | 18.16¢/kWh |
| Average monthly bill | $162.35 | $160.09 | $209.23 |
| Average monthly usage | 1149 kWh | 1057 kWh | 1152 kWh |
| Rate change, 1 year | +0.0% | +9.0% | +3.4% |
Estimate a bill at NorthWestern Energy rates
Worked example: 1,000 kWh at NorthWestern Energy's average effective rate of 14.12¢/kWh is about $141.20. The utility's actual average usage is 1149 kWh/month, which produces the $162.35 average bill. This is an all-in average (energy, delivery, fixed charges, riders); your tariff's marginal price will differ.
See the full South Dakota rate trend, look up another utility by ZIP code, or read why electric bills are rising.
Source: EIA Form 861-M (monthly utility-level sales to ultimate customers, residential), published with roughly a two-month lag. Rate = revenue ÷ sales; bill = revenue ÷ customers. Months failing basic sanity screens are excluded. See methodology.