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Rain, sleet and cold at night, Jefferson's weather notes make it online

Any television weather personality can tell you which way the wind blows, but Thomas Jefferson can now tell you if it rained in Philadelphia in July of 1776.

For some 50 years, Jefferson made nearly daily notations on the weather for wherever he lived. Now his notes can be read online as part of a cooperative effort between the Papers of Thomas Jefferson at Princeton University and the Center for Digital Editing at the University of Virginia.

“He was particularly interested in relationships of climate and geography, to know, for example, the differences in weather and climate between the Tidewater and Piedmont regions of Virginia or between North America and Europe,” James McClure, the project manager and general editor of The Papers of Thomas Jefferson at Princeton, said in an email. “He also wanted to know when produce items such as strawberries and peas would be available in the spring.”

The project’s advisory committee included several Jeffersonian scholars including Monticello’s Leslie Green Bowman, president of the Thomas Jefferson Foundation, and Annette Gordon-Reed, of Harvard University, who wrote the 1999 Pulitzer Prize-winning book “The Hemingses of Monticello: An American Family.”

Jefferson began jotting down his weather notes while attending the Second Continental Congress in Philadelphia in July 1776. With some breaks and missed dates, he continued his daily weather report until June 1826, a few days before his July 4, 1826 death.

He made more than 18,500 weather observations at locations that included Monticello and Washington, D.C.. He also noted the weather in Paris, France during his tenure as ambassador.

Jefferson’s entries include temperature, general weather conditions and sometimes details on barometric pressure, air moisture, wind direction and force, and rain or snowfall. He also often included notes on seasonal changes, wildlife and the appearance of certain bird species in the spring or the first availability of produce such as peas and strawberries.

“Jefferson’s data will be put to use by researchers investigating climate change and by historians interested in the details of weather in that period,” McClure said. “His notations about arrival of migratory birds in the spring and other seasonal aspects of plant and animal life can be used by modern ecologists interested in how those patterns may have changed through time.”

Putting the papers together and getting them online was no simple clerical task. Jefferson, as a men of his age were wont to do, wrote his notes longhand and in cursive at a time when spelling did not follow the hard and fast rules it does today. It was also a time of stylized handwriting.

“The entries in Jefferson’s weather log were all keyed from images of the original handwritten manuscripts and then carefully checked,” McClure said. “Those steps took several months of effort and involved four people. Construction of the entire digital resource took about a year and a half with a core team of six skilled individuals.”

The notes can be accessed at

Jefferson’s weather notes will eventually be joined by other records at the Center for Digital Scholarship at the American Philosophical Society as part of a planned early American weather records online platform.

The data will serve as a search engine for transcribed American meteorological records from before 1850 for researchers and fans of climate history, ecological and environmental history, and histories of science, economics, agriculture and society, officials said.

Jefferson’s digital resource is a full transcription of his handwritten records and can be seen side-by-side with images of the original manuscript pages from the collections of the Massachusetts Historical Society, the Library of Congress, the New York Public Library, the New-York Historical Society, and the Historical Society of Pennsylvania.

“This site will significantly contribute to our understanding of weather in the early national period of the United States and the history of North American climate over the last 250 years,” officials said.


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