By EV Charge Cost Editorial Team. Published September 28, 2026, updated October 26, 2026.
Your price per kWh is not the same every month. Some utilities have explicit summer and winter rates, fuel costs change with the seasons, and the way average prices are calculated adds its own seasonal wobble. Here is what the data shows and how much it matters for charging an EV.
What our data covers
We store EIA's monthly average residential price for every state, covering 14 months from July 2025 to August 2026. That spans all twelve calendar months; July and August appear twice, so we average the two years for those months. One year of data cannot fully separate a seasonal pattern from a general upward or downward trend, so treat the ranking of months as indicative.
The monthly pattern across states
| Month | Median price | EV cost per 100 mi | EV cost per month |
|---|---|---|---|
| January | 15.61¢/kWh | $5.23 | $58.83 |
| February | 15.80¢/kWh | $5.29 | $59.55 |
| March | 16.37¢/kWh | $5.48 | $61.69 |
| April | 16.54¢/kWh | $5.54 | $62.34 |
| May | 16.27¢/kWh | $5.45 | $61.32 |
| June | 16.32¢/kWh | $5.47 | $61.51 |
| July (avg of 2 years) | 15.85¢/kWh | $5.31 | $59.73 |
| August (avg of 2 years) | 16.09¢/kWh | $5.39 | $60.64 |
| September | 16.11¢/kWh | $5.40 | $60.71 |
| October | 16.08¢/kWh | $5.39 | $60.60 |
| November | 15.68¢/kWh | $5.25 | $59.09 |
| December | 15.04¢/kWh | $5.04 | $56.68 |
The gap between the most and least expensive month is 1.50¢/kWh, or 10.0%. For a 33.5 kWh/100 mi EV at 13,500 miles a year, that is $5.66 a month: noticeable, but small next to the difference between states. Looking state by state, the most expensive month fell in spring for 25 of 51 states (winter 4, spring 25, summer 15, fall 7).
Where the swings are biggest
The typical state's gap between its highest and lowest month was 15%. These states varied the most:
| State | Highest month | Lowest month | Gap |
|---|---|---|---|
| Illinois | May (23.85¢) | January (16.36¢) | 46% |
| Missouri | June (16.22¢) | December (11.76¢) | 38% |
| Hawaii | June (52.72¢) | September (39.53¢) | 33% |
| Connecticut | April (32.24¢) | June (24.32¢) | 33% |
| Iowa | August (16.27¢) | December (12.48¢) | 30% |
| North Dakota | June (14.12¢) | January (10.92¢) | 29% |
| South Dakota | May (15.73¢) | December (12.43¢) | 27% |
| Maine | February (32.17¢) | October (26.56¢) | 21% |
Why state averages can mislead here
A state's monthly figure mixes customers on many different plans. If a utility has a summer rate that is much higher than its winter rate, households on that utility see a bigger swing than the state average suggests. Customers on flat plans may see almost none. Your own bills from the last twelve months are the best record of your seasonal pattern.
Why prices move with the seasons
- Seasonal rate schedules. Some utilities charge more per kWh in their peak season, usually summer in hot regions, to reflect the cost of meeting air-conditioning demand.
- Fuel costs. Natural gas is also used for heating, so winter demand can push up the cost of gas-fired power, which is passed through to bills.
- How the average is calculated. EIA's price is revenue divided by kWh sold. Fixed monthly charges spread over fewer kWh in mild months make the average price per kWh look higher, and over more kWh in peak months make it look lower.
- Tiered rates. Where higher-use tiers cost more, heavy-use months push the average up. See tiered rates and EV charging.
What it means for EV owners
The price per kWh is only half the story. EVs use more energy in cold weather because of cabin and battery heating, so winter kWh per mile is usually higher than the EPA rating. If your utility's winter prices are also high, the two effects stack. See cold weather charging costs.
- Budget with a yearly average, not one month's bill. A high-price month followed by a low one tells you little about the year.
- Expect your EV's share of the household bill to be largest in the coldest months, when both consumption and, in some states, prices are higher.
- Check whether your utility has seasonal rates and when its peak season starts.
- On a time-of-use plan, off-peak hours usually stay cheap in every season.
Each state page shows the full monthly history for that state.