Just to be serious for a moment, a famous meteorologist once stated that the year could easily be divided into five seasons, not four, but it was winter that he divided into two: first, early winter (late Nov-mid Jan) when it tends to be wet and stormy, then late winter (mid Jan-mid March) when it usually turns drier and quieter.
I agree that May is often a bit odd; the spring flowers are over but the summer ones haven't really got going; it's warm by day but the evenings are often too cold to sit out.
Perhaps that's what Mih was thinking about.