The International Earth Rotation and Reference Systems Service (IERS) reported that Earth’s full rotation on 9 July 2025 was completed roughly 1.3 to 1.6 milliseconds faster than the standard 86,400-second day, making it the shortest day since modern atomic-clock records began in the 1950s. The acceleration continues a pattern first noticed in 2020. Astrophysicist Graham Jones of timeanddate.com expects two additional unusually brief days this summer—22 July and 5 August—when the planet could spin as much as 1.51 milliseconds faster than normal. The current all-time record is still 5 July 2024 at −1.66 milliseconds. Scientists attribute the temporary speed-up chiefly to the Moon’s position farthest from Earth’s equator, which weakens tidal braking, while interior core motions, ocean currents and atmospheric shifts may also contribute. Although imperceptible to people, sub-millisecond discrepancies matter to GPS, telecommunications and financial networks that depend on ultra-precise time signals. If the trend persists, metrologists warn they may eventually have to introduce the first-ever negative leap second—removing, rather than adding, a second to Coordinated Universal Time—to keep civil clocks aligned with Earth’s new pace.