They have a large picnic and a May Pole dance in June to welcome summer each year. South of the equator, summer comes in the calendar months of October or November. So forget the calendars. Summer comes to each depending on the vagaries of weather and the geographic location. Last I heard, it was still snowing up there.
Summer comes when it is warm enough to plant and to keep the animals outside.
Like the Celtic shepherds, we still pattern much our lives according to the rhythms of nature. This website comes from Glasgow. It's called the Celtic Shopping Mall and specializes in things Scottish. Go explore it and pretend you really are in Scotland. This is a sort of home-made site with a lot of local flavor.