Bangkok:A spectacular "double rainbow" graced the sky over the Mekong River during a longboat racing event in Mukdahan province, creating a stunning backdrop for the event. The phenomenon lasted for over half an hour, prompting many attendees to capture the moment with their mobile phones.

According to Thai News Agency, the atmosphere at the viewpoint of the Second Thai-Lao Friendship Bridge was a blend of rain and sunshine, setting the stage for the double rainbow's appearance over Muang District. The sight of the two long rainbows stretching across the river, combined with the excitement of the longboat races, left many spectators in awe.

A supernumerary rainbow, like the one witnessed, is a rare natural occurrence caused by the refraction of light twice. The primary rainbow, which is the most visible, always displays red at the top and violet at the bottom. In contrast, the secondary rainbow shows a reversal of colors, with violet at the bottom and red at the top.

Rainbows are atmospheric phenomena that result from the interaction of sunlight and water droplets in the air, acting like prisms. While the first rainbow forms at a 42-degree angle, a second, fainter, and larger rainbow can sometimes be seen about 10 degrees beyond, with its colors inverted compared to the primary rainbow.