Abstract: A system and method for dynamically changing a computer's time-related control blocks to coincide with seasonal time-of-day changes is shown including a first module for synchronizing the time-related control blocks and a second module connected to said first module for monitoring transfer of control of the time-related conrol blocks between the computer and the first module. Another system and method for dynamically changing a central processing unit time-of-day clock, without interrupting applications executing concurrently and without incurring any system down time entails transferring control of a time-of-day interpreter employing an offset to a time changer module, modifying the offset by a predetermined value at a predetermined rate until the offset reaches its synchronization value, and returning control of the interpreter to the computer. Other devices, systems and methods are also disclosed.