Solstices and equinoxes
Four times a year the Sun reaches a turning point: the two solstices bring the longest and shortest days, and the two equinoxes bring day and night of nearly equal length. In astrology these mark the start of the four cardinal signs.
The full deep dive
What they are
The Earth is tilted, so through the year the Sun climbs higher or lower in our sky.
- The solstices (around 21 June and 21 December) are the turning points when the Sun reaches its highest or lowest. They bring the longest and shortest days.
- The equinoxes (around 20 March and 22 September) are the midpoints, when the Sun is directly over the equator and day and night are close to equal everywhere.
In the southern hemisphere the seasons are reversed: the June solstice is the shortest day there.
In astrology
The tropical zodiac used in Western astrology is anchored to these four moments. The Sun enters:
- Aries at the March equinox
- Cancer at the June solstice
- Libra at the September equinox
- Capricorn at the December solstice
These four are the cardinal signs, the starters of each season. See Cardinal, fixed and mutable.
In the Chinese calendar
The Chinese calendar divides the year into 24 solar terms, including the solstices and equinoxes. The winter solstice festival, Dongzhi, is a time for family and warming food, and Lunar New Year is counted from the winter solstice.
Celebrations
People have marked these days for thousands of years, from sunrise at Stonehenge on the summer solstice to harvest festivals at the autumn equinox and festivals of light in midwinter.