Zero Shadow Day is an astronomical phenomenon that occurs twice a year in zones located between the Tropic of Cancer and the Tropic of Capricorn (approximately latitudes 23.4° N and 23.4° S).
This phenomenon happens when the sun reaches its zenith at solar noon, causing its rays to fall vertically relative to objects on the ground, resulting in no observable shadow.
A Zero Shadow Day will occur in the state of Jalisco on Sunday, May 18, and again on Friday, July 25, between 12 noon and 1 p.m. The specific date varies in other parts of the country at different latitudes.
During this period when the sun aligns directly overhead, objects that stand upright from the ground, such as utility poles, fence posts, and trees, will appear without any visible shadows outwardly.
Recommended activities to observe the brief disappearance of shadows include:
• Visit an open area like a park, lakeside Malecón, rooftop, or any location with an unobstructed view of the sky.
• Stand upright and observe your shadow become very short or entirely disappear.
• Place a water bottle or other vertical object on the ground to witness the same effect.
Zero Shadow Days are ideal for students to conduct and document science experiments related to the sun’s movement and the Earth’s tilt.