In which month does the autumnal equinox that marks the end of summer and the beginning of autumn occur in the northern hemisphere?

The correct answer is September.The SUN is vertically overhead at the equator on two days each year, these are:21ST March The Vernal Equinox and21st September The Autumn Equinox in the northern hemisphere. After the Vernal Equinox, the sun appears to move north and is vertically overhead at the Tropic of Cancer (23\( {1\over 2}\)0 N) on 21st June (in the northern hemisphere) this is KNOWN as the summer solstice.On this DAY in the Northern hemisphere experience the longest day and shortest night.By about 22 December the sun will be overhead at Tropic of Capricorn (23\( {1\over 2}\)0 S) this is the Winter solstice in the southern hemisphere.This will have its longest day and shortest night in Southern Hemisphere and vice VERSA in the Northern hemisphere.