Leap seconds face judgment day as time lords prepare to vote
A major move could end leap seconds by 2035, replacing the current UTC-UT1 tug-of-war with a broader tolerance. The General Conference on Weights and Measures is leaning toward allowing UTC to drift up to one hour from UT1 before adjustments, effectively removing the need for leap seconds for centuries. With Earth’s rotation fluctuating—even speeding up—experts say a negative leap second (subtracting a second) could be needed, a first in history, and one with uncertain impact on tech systems. If adopted, the change would secure UTC’s continuity well into the future and reduce risks tied to adding or removing leap seconds. UT1 will remain monitored and its difference from UTC shared via established services, preserving the link for astronomy and navigation while simplifying everyday timekeeping for global networks and critical infrastructure.