Ne'er (Never) cast a clout 'til May be out In english explanation

This is a proverb that may have exist for a long time under many versions. Before it first official citation as the curren version in a poem in 1732 by Dr. Thomas Fuller named 'Gnomologia' , it may have existed in word-of-mouth form. The proverb origin is still a battling question but the English version has been identified to be first appeared in Captain John Stevens's work, 'A New Spanish and English Dictionary', published in London, 1706, which translated from a Spanish proverb as "Do not leave off your Coat till May be past". But many people believed that the proverb was originated in England, the Spanish just coined it into their own version and then it was translated to English. 

Another meaning of the proverb is an old English (and ancient Greek) superstition about not prematurely donning new clothing during the month of May as May is the unlucky month. This was first cited in 'The White Goddess (1948)'  written by Robert Graves.