The vertical ray of the sun, also known as the solar declination, strikes the Earth at the equator on the spring and autumn equinoxes.

However, throughout the year, the solar declination changes. It moves north of the equator from the vernal equinox (March 20/21) to the summer solstice (June 20/21), reaching a maximum of 23.5 degrees north latitude (the Tropic of Cancer). Then, it moves back south, passing the equator again on the autumnal equinox (September 22/23), and reaching 23.5 degrees south latitude (the Tropic of Capricorn) on the winter solstice (December 21/22).

So, the answer depends on what time of year you're asking about!