14th August 2022 – (Hong Kong) There were occasional showers yesterday but temperature has risen. Under the unsettled weather conditions, a double rainbow appeared again yesterday in Tai Po after last Friday (5th). Some citizens took pictures and shared them on social media. The double rainbow was spotted near Tai Po Waterfront Park and Tai Po Industrial Estate. Double rainbows are formed when sunlight is reflected twice within a raindrop with the violet light that reaches the observers eye coming from the higher raindrops and the red light from lower raindrops.
Surprisingly, this phenomenon is actually relatively common, especially at times when the sun is low in the sky such as in the early morning or late afternoon. The second rainbow is fainter and more ‘pastel’ in tone than the primary rainbow because more light escapes from two reflections compared to one.
The secondary rainbow is also dispersed over a wider area of the sky. It is nearly twice as wide as the primary bow.
A key feature of double rainbows is that the colour sequence in the second rainbow is reversed, so instead of red, orange, yellow, green, blue, indigo and violet (ROYGBIV), the colours appear in VIBGYOR order.