Getting timezone offset is crucial for handling date calculations across different timezones and converting between local and UTC times in JavaScript applications. As the creator of CoreUI, a widely used open-source UI library, I’ve handled timezone calculations in countless global applications over 25 years of development. From my expertise, the most reliable approach is using the getTimezoneOffset() method, which returns the difference in minutes between UTC and local time. This provides the foundation for accurate timezone-aware date operations.