During which two months of the year does a solstice occur?

• A. December and June
• B. March and September
• C. May and November
• D. January and July

Answer: (A)

Solstices mark the Sun’s extreme positions in the sky because Earth is tilted on its axis and orbits the Sun. This tilt means the Sun appears at its highest point in the sky at noon on one day each year and at its lowest on another, creating the longest and shortest days of the year. Those two moments happen roughly every six months: around June 21 and around December 21. In the Northern Hemisphere, the June solstice gives the longest day and signals the start of summer, while the December solstice gives the shortest day and signals the start of winter. The same two months apply in the Southern Hemisphere, though seasons are opposite there. Other options correspond to equinoxes or other times of the year when day length isn’t at an extreme, so they don’t fit the idea of a solstice.