An electronic timer may include a clock reference signal generator and a real time clock (RTC) circuit for generating real time data based upon the clock reference signal. The RTC circuit may include a plurality of registers each for storing a respective bit of the real time data. Further, each register may include a master latch for initially storing the real time data bit, a slave latch for subsequently storing the real time data bit, and a user latch for storing the real time data bit from the slave latch. The RTC circuit may further include a controller for causing at least some of the registers to increment based upon the clock reference signal. Additionally, the electronic timer may also advantageously include a tamper circuit for receiving a tamper event signal and causing each of the user latches to hold a time stamp therein.