Lahaina Noon

Lāhainā Noon, also known as a zero shadow day, is a semi-annual tropical solar phenomenon when the Sun culminates at the zenith at solar noon, passing directly overhead (above the subsolar point).^[1] As a result, the sun's rays will fall exactly vertical relative to an object on the ground and cast no observable shadow.^[2] A zero shadow day occurs twice a year for locations in the tropics (between the Tropic of Cancer at approximate latitude 23.4° N and the Tropic of Capricorn at approximately 23.4° S) when the Sun's declination becomes equal to the latitude of the location, so that the date varies by location.^[3] The term "Lāhainā Noon" was initiated by the Bishop Museum in Hawaiʻi.^[4]