Laying in my garden on Thursday trying to soak up some rare spring warmth I spotted this rainbow directly overhead. Turns out it is no rainbow but a circumhorizontal arc, an optical phenomenon, sometimes known as an ice halo ,formed by the refraction of the sun through ice crystals.
According to Wikipedia it is a rare occurrence in Northern Europe as it depends on ice crystals appearing in the right part of the sky and the sun being very high. The fascinating, but sometimes incorrect, Wikipedia tells me that it is only possible to see this in England between mid May and late July. So what was it doing above my garden on the 2nd April? A late April Fool played by the heavens maybe.