In reply to Pesda potato:
Because if it was in mid summer it would make a nonsense of a lot of the carols.
Why would shepherds want to wash their socks by night, all seated round the fire? Who needs a fire in mid summer?
And what about King Wenseslas? How could he walk through deep and crisp and even snow in mid summer?
But, yes, when I was working I would much rather have had a nice long holiday in the summer than at the grottiest time of the year.
The folk in the Southern Hemisphere have got it made, so expect opposition to any proposed date change.......