Summer is one of the four temperate seasons. Astronomically, it begins with the summer solstice (around 21 June in the Northern hemisphere, and 21 December in the Southern hemisphere), and ends with the autumn equinox (around 21 September in the Northern hemisphere and 21 March in the Southern hemisphere).An exception to is in the Irish Calendar, which still follows the Celtic cycle, where it is counted as the whole months of May, June and July. However, sometimes it is counted instead as the whole months of December, January and February in the Southern hemisphere and June, July and August in the Northern hemisphere.
