Gally, a little more info might be helpful.
Peak hours for going clubbing?
Peak hours for commuting?
Peak hours for electrical consumption?
Peak hours for sleeping?
Off hand I'd say peak hours are Monday - Friday 8am - 6pm. Those are the predominant business hours.
There is a device called a 'time of use meter'. This is an electrical meter issued by the utility companies that monitor and charge for electric based on the time of day of your electrical usage. The rates are lowest between approx. 11pm thru 6am. However, there are normally a few time blocks throughout the day, on-peak, off-peak, mid-peak and sometimes super-peak. Also the season has an effect on the rates. Summer and winter seasons have different rates with summer being higher.