These occur when the sun is directly over the equator, making day and night nearly equal in length.
The transition of seasons triggers significant biological and environmental shifts: change of season dates
If you are looking for the official astronomical start dates for the Northern Hemisphere, mark your calendars for these transitions: Summer (Summer Solstice) Fall (Autumnal Equinox) Winter (Winter Solstice) These occur when the sun is directly over
: Meters use these dates to automatically switch between different billing rates (e.g., Summer vs. Winter tariffs). Summer vs. Winter tariffs).