The Jumping Clock
macOS is designed for mobile professionals, and its default behavior is to rely on Wi-Fi and Location Services to automatically pinpoint where you are in the world. When you travel across a border, the operating system detects the new location and automatically changes your system clock’s time zone to match local time. While usually convenient, this feature can be incredibly disruptive if you work remotely for a company in a different time zone and need your computer’s clock to remain anchored to headquarters time, or if Location Services misidentifies your IP address and aggressively shifts your clock forward or backward randomly throughout the day.
Anchoring Your Time Zone
To ensure your system clock remains exactly where you want it and stop macOS from automatically changing the time zone, you must disable the location-based time tracking in the system settings.
Click the Apple logo in the extreme top-left corner of your screen and select System Settings. In the left-hand navigation sidebar, scroll down and click on General. In the right-hand panel, click on Date & Time. Look for the toggle switch explicitly named Set time zone automatically using your current location. (You may need to authenticate with your password or Touch ID to unlock this setting). Click this toggle to turn it Off. Immediately below this setting, you will see a text field labelled Closest City. You can now manually type in your preferred city (e.g., London, New York) to permanently lock your Mac to that specific time zone, regardless of where you physically travel.