Summary:
- The seasons are caused by the 23.5° tilt of Earth’s axis.
- One hemisphere points more directly toward the Sun than the other hemisphere.
- At equinox, the Sun is directly over the Equator.
- Summer solstice is June 21 or 22 in the Northern Hemisphere.
- At winter solstice, the sun is closest to the South Pole (around December 22) The time is 9:00 p.m. Universal Time, at Greenwich, England, for summer solstice.