Spot gold trades from about 22:00 UTC Sunday to 21:00 UTC Friday with a daily rollover break near 21:00 to 22:00 UTC.
The Asian session (23:00 to 07:00 UTC) typically ranges, the London open (07:00 to 09:00 UTC) expands the range and frequently sweeps the Asian high or low, and the London and New York overlap (13:00 to 17:00 UTC) carries the deepest liquidity and largest directional moves. The two most costly windows are the rollover and the 13:30 UTC US data release.