Lunar Rainbows

A Lunar Rainbow

Each full moon the Victoria Falls rainforest re-opens in the evening for special tours to witness the mystical magic of the lunar rainbow - spray and cloud permitting!  The Victoria Falls are one of the few places on earth where this natural phenomenon occurs regularly and where it can be witnessed with ease. And yet many people visit the Falls without knowing of this natural phenomenon but it is one of the most impressive sights of Victoria Falls.

Lunar rainbows are much fainter than their day-time forms with which we are all so familiar. This is because of the lower amount of light reflected from the surface of the moon. Only when the moon is full and skies clear of cloud is enough light reflected to create a moonbow, which always occur in the sky opposite from the moon in relation to the observer.

The human eye finds it difficult to discern the colours in the moonbow because the light is usually too faint from the moon to excite the human eye cone colour receptors (this is true of all night-time vision). Hence, moonbows often appear to the human eye to be washed-out and white, without the concentrated colours of a day-time rainbow. However, the colours of a lunar rainbow do show in photographs with a long exposure.

The lunar rainbow is best seen at times of high water (April to July) when there is sufficient spray to create the moonbow effect. This spectacle is best witnessed in the early hours after moonrise, before the moon rises too high to create a moonbow that is visible to the ground-based observer.

The rainforest opens and operates tours the night before, night of and night after the Full Moon (see chart below for dates), when the moon is at its brightest and the chances of seeing a moonbow are greatest. .

Dates on which the Victoria Falls National Park is open for lunar rainbow tours.

Year
2017

Night
Before

Full
Moon

Night
After

January

February

March

April

May

June

July

August

September

October

November

December

11

10

11

10

9

8

8

6

5

4

4

2

12

11

12

11

10

9

9

7

6

5

5

3

13

12

13

12

11

10

10

8

7

6

6

4