The attached picture can be credited to an astronomer living near Cambridge, United Kingdom. She is positive she has never seen anything like it in her 60 years of existence.
Apparently, the upside-down rainbow is created by very specific climatic conditions. Such conditions have just never occurred outside of the polar regions before.
This freak of nature is a product of light bouncing off ice crystals high in the atmospher. The deflection causes the rainbow to shoot upwards rather than downwards. But it can only work with just the right crystals and when the sky is absolutely clear.
The British Met Office confirms that such freaks have occasionally been spotted in the past. But the moment is rare enough for all of us to enjoy nature smiling back at us.