I was wondering why we celebrate Christmas in December instead of in April when Jesus Christ was really born?
No definite date has been established for the birth of the Savior. Our notion that he was born in April comes from D&C 20:1, which states
The rise of the Church of Christ in these last days, being one thousand eight hundred and thirty years since the coming of our Lord and Savior Jesus Christ in the flesh, it being regularly organized and established agreeable to the laws of our country, by the will and commandments of God, in the fourth month, and on the sixth day of the month which is called April.
This statement only specifies that the Church was organized 1830 years after the birth of the Savior. The statement, however, specifies April 6 as the day of the organization of the Church, not the day of the Savior’s birth.
Elder Bruce R. McConkie has made the following statement on the subject:
“We do not believe it is possible with the present state of our knowledge-including that which is known both in and out of the Church-to state with finality when the natal day of the Lord Jesus actually occurred” (The Mortal Messiah, Vol.1, Footnotes, p.349).
If, indeed, the Savior was born in the month of April, the official birthday was designated by the Roman emperor Constantine in 325 A.D. to coincide with the winter solstice. This was done to placate the Pagans who worshiped the seasons of the year. So, when the Church was organized Christmas was well established as December 25. The Church has not taken issue with the traditional date for the celebration of Christmas.