Daily Observation Records
Jefferson’s logs of his own daily meteorological observations span half a century, from July 1776 to June 1826, with gaps and some duplication. Most of the pages are in five bound volumes, the originals of which are in the Coolidge Collection of Thomas Jefferson Manuscripts at the Massachusetts Historical Society, the Jefferson collection at the Library of Congress, and the New York Public Library. In each case, the weather diary pages are bound with pages of Jefferson’s financial accounts or miscellaneous memoranda. Two individual leaves, one at the Historical Society of Pennsylvania and one at the New-York Historical Society, appear to have once been part of the bound record at the Library of Congress.
Some other tables by Jefferson, not part of his primary daily record, take the form of daily observations and are grouped here with his weather diaries.
Also in Jefferson’s papers, and to be included on this site, are several daily registers made by other observers.
For a description, images, and transcription of a document, click on its image or label below. The transcription view displays the entry as it appears in the original manuscript, including abbreviations and fractions. Click on the View Data link to see the content of the entry in a standardized format.
Other Weather and Climate Documents
A second category of texts includes documents from Jefferson’s papers that relate to climate or weather but are not records of daily observations.
Several of these texts have been extracted from the pages of the bound daily observation records. Some are notes Jefferson made regarding his observation procedures (for example, Note on “Rejected” Temperatures, ca. June 1799), and some record data from a period of time (such as Recapitulation of Depth of Snows, 1802–1803 to 1808–1809). Two of the documents record daily observation data but can best be understood apart from the main weather diaries. One of these is a table of observations from Jefferson’s voyage across the Atlantic in July 1784 on his way to France. The other document, labeled Bedroom Temperatures, 1802–1804, consists of columns of data that Jefferson incorporated into his observation record for a little more than a year beginning in December 1802. Those entries consist of readings from a thermometer placed in an unheated interior room, with notes of how far the room’s window was open overnight (not all of Jefferson’s notations in these entries are understood). Although he incorporated this data with his daily weather observations for the period, these entries constitute a discrete set of experimental data.
The texts in this category appear as transcriptions only. Their content has not been incorporated into the dataset of daily observation records accessed through the functions of the Search page.