Which equinox defines the start of spring?

Which equinox defines the start of spring?

• A. day and night equal length marking start of autumn
• B. longest day of the year marking the start of summer
• C. day and night equal length marking the start of spring
• D. shortest day marking the start of winter

Answer: (C)

Equal day and night length happens at an equinox, when the Sun appears directly above the equator. The vernal (spring) equinox occurs in late March in the Northern Hemisphere and signals the start of spring. The longest day happens at the summer solstice, the shortest day at the winter solstice, and the other equinox marks autumn. So, the statement about day and night being equal in length at the spring equinox best describes the start of spring.

Equal day and night length happens at an equinox, when the Sun appears directly above the equator. The vernal (spring) equinox occurs in late March in the Northern Hemisphere and signals the start of spring. The longest day happens at the summer solstice, the shortest day at the winter solstice, and the other equinox marks autumn. So, the statement about day and night being equal in length at the spring equinox best describes the start of spring.