Almost the entire month of November falls during the liturgical season known as Tempus per Annum or Ordinary Time (formerly Time After Pentecost), which is represented by the liturgical color green. Green is a symbol of hope, as it is the color of the sprouting seed and arouses in the faithful the hope of reaping the eternal harvest of heaven, especially the hope of a glorious resurrection. The liturgical color green is worn during the praying of Offices and celebration of Masses of Ordinary Time. The last portion of the liturgical year represents the time of our pilgrimage to heaven during which we hope for reward.

The last day of November is a Sunday and marks the beginning of Advent. The liturgical color changes to purple, representing a time of penance and preparation.

Thanksgiving
The national holiday (USA) of Thanksgiving also falls on the last Thursday of November. There are special Mass propers which may be used on this day. (Read more here.)

The tradition of eating goose as part of the Martin's Day celebration was kept in Holland even after the Reformation. It was there that the Pilgrims who sailed to the New World in 1620 became familiar with this ancient harvest festival. When, after one year in America, they decided to celebrate a three days' thanksgiving in the autumn of 1621, they went in search of geese for their feast. We know that they also had deer (a present from the Indians), lobsters, oysters, and fish. But Edward Winslow, in his account of the feast, only mentions that "Governor Bradford sent four men on fowling that so we might after a more special manner rejoice together, after we had gathered the fruit of our labours." They actually did find some wild geese, and a number of wild turkeys and ducks as well.

The Pilgrim Fathers, therefore, in serving wild turkeys with the geese, inaugurated one of the most cherished American traditions: the turkey dinner on Thanksgiving Day. They also drank, according to the ancient European tradition, the first wine of their wild-grape harvest. Pumpkin pie and cranberries were not part of the first Thanksgiving dinner in America, but were introduced many years afterward.

The second Thanksgiving Day in the New World was held by the Pilgrims two years later, on July 30, 1623. It was formally proclaimed by the governor as a day of prayer to thank God for their deliverance from drought and starvation, and for the safe arrival from Holland of the ship Anne.

In 1665 Connecticut proclaimed a solemn day of thanksgiving to be kept annually on the last Wednesday in October. Other New England colonies held occasional and local Thanksgivings at various times. In 1789 the federal Congress authorized and requested President George Washington to proclaim a day of thanksgiving for the whole nation. Washington did this in a message setting aside November 26, 1789 as National Thanksgiving Day.

After 1789 the celebration reverted to local and regional observance for almost a hundred years. There grew, however, a strong desire among the majority of the people for a national Thanksgiving Day that would unite all Americans in a festival of gratitude and public acknowledgment for all the blessings God had conferred upon the nation. It was not until October 3, 1863, that this was accomplished, when President Abraham Lincoln issued, in the midst of the Civil War, a Thanksgiving Proclamation. In it the last Thursday of November was set apart for that purpose and made a national holiday.

Since then, every president has followed Lincoln's example, and annually proclaims as a "Day of Thanksgiving" the fourth Thursday in November. Only President Franklin D. Roosevelt changed the date, in 1939, from the fourth to the third Thursday of November (to extend the time of Christmas sales). This caused so much consternation and protest that in 1941 the traditional date was restored."
—Excerpted from the Handbook of Christian Feasts and Customs, Francis X. Weiser