Thailand begins its first “Sun Overhead” cycle of the year in Yala, creating a rare shadowless effect—though experts warn it may not be the hottest day.
Residents across Thailand’s 77 provinces are set to experience a rare astronomical curiosity over the coming weeks as the sun reaches its zenith directly overhead, momentarily rendering shadows invisible.
The National Astronomical Research Institute of Thailand (NARIT) has released a comprehensive timeline for the first of the year’s two “Sun Overhead” events. The cycle commenced today, 4 April 2026, in the southernmost district of Betong, Yala, at precisely 12:19 PM.
During this window, anyone standing outdoors will notice that their shadow—and those of vertical objects like lamp posts—falls directly beneath them, creating a “shadowless” illusion.
A Northward Journey
According to Suparerk Karuehanon, assistant director of NARIT, the phenomenon does not occur simultaneously across the country.
Because of the Earth’s curvature, the sun’s 90-degree vertical alignment will gradually “march” northwards through April and May.
The Starting Point: Betong, Yala (4 April at 12:19 PM).
The Final Destination: Mae Sai, Chiang Rai (22 May at 12:17 PM).
A second cycle is expected later in the year, between July and September, as the sun’s relative position moves back from the north towards the south.