Daylight saving time starts at 2 in the morning, the second Sunday in March, when the clocks are set one hour ahead. Daylight saving time detractors say that scientific studies evaluating the impact of the shift in hourly policy to daylight saving time in Indiana have identified a significant increase in energy use and electricity spending by Indiana households. Debate in the city, the Indiana General Assembly passed a law to place all of Indiana on central standard time and ban daylight saving time. Several counties in eastern Indiana (Ohio and Dearborn Counties, near Cincinnati; and Floyd, Clark and Harrison Counties, near Louisville) chose to unofficially observe daylight saving time, despite Indiana law.
Supporters of daylight saving time and a common time zone in Indiana often assert that Indiana must adopt the Eastern United States timing system to preserve interstate business with that region. Indiana enacted the statute, officially placing northwest and southwest Indiana in the central time zone, in observance of daylight saving time, and the rest of the state in Eastern Standard Time throughout the year.