Across the world, the changing of the seasons shapes our weather, traditions, and daily routines. But what many people don’t realize is that each season actually begins twice. This isn’t just a quirk of calendars; it’s the result of two different systems scientists and forecasters use to define seasonal change. From shifting daylight to temperature cycles, these systems affect how we experience spring, summer, autumn, and winter.
Click on to explore why every season starts twice.