Where You Live
The state you live in will affect your electric rates more than whether it's winter or summer. It ranges from a low of about 8 cents per kilowatt hour in Washington to over 19 cents in New York and 28 cents in Hawaii.
Time of Use Rates
Some states, such as Wisconsin, offer optional time of use electricity rates. This means your electricity rates are more expensive between 9 a.m. and 10 p.m. (the peak hours), than between 10 p.m. and 9 a.m. (considered off-peak). Peak rates are more expensive in the summer than in the winter because of air conditioning. You can save money on one of these plans if you are able to shift some of your electricity use to off-peak hours.
Considerations
You can reduce your electricity costs year round by using a programmable thermostat so you can keep your house cooler in winter and warmer in summer when you're not home or when you're sleeping. Be sure to check weather stripping seasonally and insulate your home properly to further reduce your costs, whatever the season.