Fire ~ Water ~ Earth ~ Air
The astronomical explanation uses the dates of equinoxes and solstices to mark the beginning and end of each season.
- Spring begins on the spring equinox;
- Summer begins on the summer solstice;
- Fall (autumn) begins on the fall equinox; and
- Winter begins on the winter solstice.
The beginning of each season marks the end of the last.
Since the timings of the equinoxes and solstices change each year, the length of astronomical seasons within a year and between years will vary.