December 21or 22

North end of Earth's rotational axis is pointing away from the sun

June 20 or 21

North end of Earth's rotational axis leans along Earth's orbit. (Towards the sun)

March 20 or 21

North end of the Earth's rotational axis leans along the Earth's orbit towards the sun

September 22 or 23

North end of the Earth's axis leans along the Earth's orbit. (Away from the sun)

Equinox and Solstice