Chasing Rainbows in Victoria Falls

Who doesn’t like rainbows? Victoria Falls is one of the most spectacular natural wonders on the planet, but its beauty isn’t limited to the views of the falls themselves. Endless rainbows, optical phenomenon, caused by the reflection, refraction and dispersion of light in the water droplets of the spray, seem to be everywhere you look at the Falls, somehow adding an extra layer of magic to an already mesmerizing destination. Whether you’re a nature lover, a photographer, or simply someone who appreciates nature’s beauty, seeing the rainbows at Vic Falls are a definite for your bucket list.

While daytime rainbows are a common sight at Victoria Falls, lunar rainbows are a much rarer occurrence. Also known as ‘moonbows’, lunar rainbows are rainbows formed by the light of the moon rather than the sun. This creates a much fainter and more elusive rainbow and one that can only be seen under very specific conditions. The Victoria Falls is the only place in Africa, and one of only a handful of places in the world, where the incredible natural phenomenon can be seen – something surprisingly few people who visit the Victoria Falls seem to know!

To see a lunar rainbow at Victoria Falls, you’ll need to be in the right place, at the right time. The best time to see a lunar rainbow is during a full moon, when the moon is at its brightest and the sky is clear. You’ll also need to be at the Falls at night, as lunar rainbows are only visible in the dark.

The first mention of a ‘moonbow’ was made way back in 350 BC, by the famous Greek philosopher Aristotle. Benjamin Franklin bagged a sighting or two, as did Mark Twain and 19th century mountaineer John Muir. The hunt for the elusive ‘moonbow’ has long been a quest for hikers, insomniac seamen and intrepid photo buffs. In the past, seeing one of these night time rainbows was dictated mostly by chance. No longer. At Victoria Falls, the moon’s light refracts through the mist of the falls, creating a breathtaking and otherworldly sight in the night sky for all to see.

A lunar rainbow, much like a solar rainbow, is an optical phenomenon caused by the refraction, or bending, of light through water droplets in the air. When the light from the moon passes through these droplets, it splits into the individual colours of the spectrum, just as it does with a solar rainbow. However, unlike their daytime counterparts and due to the dinner light of the moon, lunar rainbows are more rare and less vivid. In fact, the colours of a lunar rainbow can sometimes be too dim to be detected by our eyes’ colour-detecting cells, resulting in a ghostly white appearance (especially the older you get!).

The conditions for witnessing a lunar rainbow are quite specific. Lunar rainbows are only visible when the moon is full, or nearly full, and the sky is clear with minimal cloud cover. The best places to see lunar rainbows are where there are waterfalls, mist, or any other falling water.

In order to see lunar rainbows clearly, it’s essential to be in areas with very little light pollution. Consequently, the best places to see them are usually remote locations.

Lunar rainbows are only be found in a handful of places around the world, including Wallaman Falls (Australia), Skogafoss Waterfall (Iceland), Yosemite Falls (USA), Kihei Falls (USA), Cumberland Falls (USA), and Victoria Falls. In fact, there are only two places on Earth where lunar rainbows can be seen consistently and with relative ease: Cumberland Falls in Kentucky, USA and the Victoria Falls, on the border of Zambia and Zimbabwe. For three days during every month, when the conditions are right, moonbows light up the night sky at the Victoria Falls.

If you want to witness the magical phenomenon of a lunar rainbow at Victoria Falls, plan your visit during the Zambezi’s high-water season, February – August. The absolute best time to see this amazing spectacle April – July, when water flow is at its peak, and the moon is bright and consistent. It is also advisable to check the weather forecast and plan your visit on a clear night to increase your chances of success. Keep in mind that after July, the cool dry season sets in, reducing waterflow/spray and increasing wind speeds, making it difficult to witness a lunar rainbow.

The best viewpoint to see a lunar rainbow at Victoria Falls is in Zambia, along the Eastern Cataract. If you’re visiting from June to August, the view from the Eastern Cataract can’t be beaten. On the Zimbabwean side you’re a bit more limited for options, due to the narrowness of the gorge in places. In Zimbabwe, the best spot to view the lunar rainbow is at viewpoint 7 (sometimes referred to as Cataract Island viewpoint) looking west towards Devils Cataract.

If you’re travelling with a group, consider taking a guided tour of the Falls. This will include pick-up and drop-off from your hotel as well as the entrance fee, and once you’re inside your guide will be able to take you to the best view points.

Remember to keep you voice low and your flashlight off! There’s no need for a flashlight, the moonlight is more than sufficient. It’s also irritating to other when you flash your light on them when they are trying to enjoy the view, and doing so impairs their night vision. Remember that you’re on the edge of a large chasm, so don’t overdo it on the beers and wine, you don’t want to go tumbling over the edge!

The entrance to the Falls, on both the Zambian and Zimbabwean sides, is open on the night of a full moon, as well as the night before and night after – but note that if the weather is too cloudy, the gates will not open, and there will be no advance notice of this. Also bear in mind that lunar rainbows are only visible during the full moon the high-water season.

Incidentally, the lunar rainbow can also be viewed from the Victoria Falls bridge.

The human eye finds it difficult to discern the colours in a lunar rainbow because the moonlight is usually too faint for the eye’s colour receptors, so if your expectations of a bright rainbow are too high, you might be disappointed. But good news, the colours of the lunar rainbow show up clearly in photos taken with a long exposure. So, ditch the flash and try a shutter speed of 10 seconds and ISO 800 (there are phone apps that let you manipulate shutter speed). A tripod or bean bag set-up can be useful for shaky hands, but you can also balance your phone or camera on your knee or some other stable surface.

Oscar Wilde might once have said “When it rains look for rainbows, when it’s dark look for stars.” But at Victoria Falls, with a lunar rainbow, you can have both – rainbows and stars. If you’re looking for a unique experience in Africa, then the Victoria Falls lunar rainbow is definitely for you.