[Written by NOAA] On November 26, 1863, residents near Plymouth, Massachusetts celebrated the first federally recognized Thanksgiving holiday. While it is thought that one of the first Thanksgivings took place in Plymouth in the early 1600s, it was not until a proclamation issued by President Abraham Lincoln in the fall of 1863 that a specific day of thanks was recognized. It was a sunny day with a high near 40°F and slight winds from the northwest. In 1863, the closest weather station to Plymouth was in Fort Warren, Massachusetts. There, the U.S. Army recorded weather observations while they used Fort Warren to protect the Boston Harbor from the Confederate Navy. Their observations indicate that November 1863 was a warm one for eastern Massachusetts, with some light snow early in the month and many days with highs in the 50s. NOAA's National Centers for Environmental Information is responsible for storing data like the U.S. Army’s 1863 Thanksgiving surface weather observations. Their archive of environmental data is the largest in the world, with over 38 petabytes of digital data available to users, which includes a copy.  A team of experts works to ensure the quality and integrity of these data for present and future generations.