The first mention of the phrase, “Christmas in July” is found in Werther, an 1892 French opera with libretto by Édouard Blau, Paul Milliet, and Georges Hartmann. It had an English translation published in 1894 by American playright, Elizabeth Beall Ginty. In the story, a group of children rehearses a Christmas song in July, to which a character responds: "When you sing Christmas in July, you rush the season."
The earliest known celebration in the United States to make the phrase Christmas in July literal was in July, 1933 at Camp Keystone, a girl's summer camp in North Carolina which celebrated with a Christmas tree, gifts, and a visit by Santa Claus. In 1935, the National Recreation Association's journal Recreation described what a Christmas in July was like at a girl's camp, writing that "all mystery and wonder surround this annual event." It was definitely something that the girls looked forward to.
American advertisers began using Christmas in July themes in print for summertime sales as early as 1950. In the United States, it is more often used as a marketing tool than an actual holiday. Television stations have chosen to re-run Christmas specials, and many stores have Christmas in July sales. Some individuals choose to celebrate Christmas in July themselves, typically as an intentionally transparent excuse to have a party. This is in part because most bargainers tend to sell Christmas goods around July to make room for next year's inventory.
People who love the season sometimes use "Christmas in July" as the kick off to start talking, planning and buying things they need for the upcoming holiday. It has become the official start -- to the most wonderful season on earth!