Question: Why is Thanksgiving celebrated on the fourth Thursday of November?
Answer: In 1939, November had five Thursdays, so retailers asked President Franklin D. Roosevelt to push Thanksgiving back a week to give people more time for holiday shopping. Roosevelt agreed, but many state governors wanted to keep the holiday on the last Thursday of the month. To solve the problem, Congress passed a law in December 1941 proclaiming that Thanksgiving would be celebrated on the fourth Thursday of November, effective November 1942.
Bonus info: Americans have celebrated Thanksgiving on the fourth Thursday in November since 1942, but numerous other dates were designated in the past. It all started with the Pilgrims in fall of 1621, but beginning in 1668, it was celebrated on Nov. 25. That lasted only a few years.
In 1789, President George Washington decreed it would be celebrated on Nov. 26, but the holiday bounced from month to month and date to date in the years that followed. In 1864, the last Thursday in November became the norm after President Abraham Lincoln declared it to be held that day. It was customarily the fourth Thursday of November.