Figure 1. Thomas Jefferson and James Madison are best known for their contributions to the documents that established the United States and for their service as presidents of the young republic. Yet each man’s intellectual range extended well beyond matters of planting and governing. Jefferson began recording weather while still a student at Williamsburg, and he later encouraged his close friend Madison to do the same. Initially, both followed procedures recommended by the Royal Society of London, which specified that temperatures be taken in a north-facing room where fires were rarely lit. Madison first broke the rule by beginning to take measurements outdoors, and Jefferson later followed suit. The approach eventually evolved to the ubiquitous louvered white boxes common to contemporary weather stations. Shown here is the modern station at Jefferson’s Monticello.
Figure 2. Jefferson’s Monticello and Madison’s Montpelier lay 21 miles apart in the Piedmont of Virginia. Contemporary weather stations are located at Monticello (a) as well as near Charlottesville (b and c) and near Montpelier at Piedmont Research Station (d). (Data from these stations can be obtained at http://www.ncdc.noaa.gov.)
Figure 3. Madison and Jefferson recorded temperatures at sunrise and 4 p.m. Shown here are the June monthly mean differences between those temperatures for months in which their records provide at least 10 daily values from 1777 through 1816. Note the large increase in difference for Madison’s readings (red) when he moved his thermometer outdoors in 1786; Jefferson (blue) began to capture the full difference between afternoon and morning temperatures when he moved his thermometer to the northeast portico in the late 1790s and outdoors in 1803. Jefferson’s data for 1814 include some observations at Poplar Forest, approximately 60 miles from Monticello. The white line is the mean difference recorded at the Charlottesville weather station from 1973 through 2006. Orange shading shows one standard deviation from the mean; the outer bound of the pink shaded area shows the minimum and maximum recorded difference. (Jefferson’s data are largely given in his Memorandum Books, whereas those of Madison can be found in his Papers [see bibliography]. Their original documents are archived at the Massachusetts Historical Society, the American Philosophical Society and the Presbyterian Society of Philadelphia.)
Figure 4. The northeast portico of Monticello (above) was where Jefferson recorded weather. His wind vane (upper right) could be read on the ceiling inside (lower right). At least in the colonies, designing features of a home for scientific observation was unprecedented at the time.
Figure 5. Starting in 1786, Madison and his family recorded temperatures on the porch of Montpelier.
Figure 6. In 1790, Madison was measuring temperature outside and Jefferson inside. Jefferson’s sunrise and 4 p.m. temperatures (blue) showed much smaller daily differences than those taken at Montpelier (red) during February 1790.
Figure 7. As can be seen in these samples from the records kept by the Madison family, temperature, wind direction and sky state were recorded twice per day by these avid amateur scientists.
Figure 8. When monthly mean temperatures taken by Jefferson from 1803 through 1816 (blue) and Madison from 1787 through 1802 (red) are compared to modern data taken at Charlottesville (black) and the Piedmont Research Station (dashed black) from 1951 through 2000 and at Monticello from 1982 through 2003 (dotted black), they track relatively well. Although amateurs, Jefferson and Madison were meticulous. (As in Figure 3, orange shading shows one standard deviation and pink shows the extremes of modern Charlottesville data.)
Figure 9. Madison moved his thermometer outside when he realized that his readings seemed too warm on a day when ice formed on trees. Once the thermometers were outside, the mean daily average temperatures became consistent with those of modern data when snow accumulation of at least one inch is observed, as shown here. (Error bars are one standard deviation.)
Slightly off, here are some past Historic Winter Weather during Jefferson and Madison's time.
18th Century Winters
Washington and Jefferson Snow Storm, Jan. 28, 1772: Recorded in both George Washington's and Thomas Jefferson's diaries, the storm left 30 to 36 inches of snow from Charlottesville to Winchester to Washington, D.C., and remains the unofficial record. The deep snow pack prevented travel for up to two weeks, and postal service was stopped for five weeks.
May 4, 1774: Snow was reported in the Williamsburg Gazette to have fallen in Dumfries, Va. George Washington's at Mount Vernon, logged in his diary a cold day with spits of snow and a hard wind from the northwest. Thomas Jefferson near Charlottesville observed the Blue Ridge Mountains covered with snow. The late-season snow and frost killed most of the fruit crop in the northern part of the state.
Dec. 25, 1776: Thomas Jefferson noted that the first winter snow fell on Dec. 20, but did not last on the ground one day. Temperatures dropped to 30°F or colder on Christmas Day. That night, 22 inches of snow fell. From the 20th of December until March 6, 10 snows covered the ground and some of them were deep. The first rain came on the 9th of March. In Frederick County, two feet of snow was recorded.
The Hard Winter of 1779-1780: This winter was so cold that ice was said to have been piled 20 feet high along the Virginia Coast and stayed there until spring. The upper portion of the Chesapeake Bay was frozen, allowing people to walk from Annapolis to Kent Island, Md. The Virginia portion of the Bay was frozen near the mouth, as well as all waterways in Virginia, which were firm enough to support the crossing of a regiment of the Virginia Infantry fighting the War of Independence as it marched from Falmouth to Fredericksburg, crossing the Rappahannock River, which had been frozen since the previous November.
The Long Winter of 1783-1784: Not as cold as 1780, this winter lasted longer into the spring, and was thought to rank near the top for extremes in cold and snow. The Chesapeake Bay once again froze almost all the way to the mouth. James Madison in Orange County, Va. wrote in a letter to Thomas Jefferson, "We had a severer season and particularly a greater quantity of snow than is remembered to have distinguished any preceding winter." The thaw caused an ice jam on the James River at Richmond that gave way, causing a flash flood of ice and water that swept away a bridge and sank boats that were tied up below the falls. Ice on the Potomac did not break until March 15th.
Jan. 1792: The Elizabeth River at Norfolk froze for the first time since 1784.
Feb. 14, 1798: The Norfolk Herald on Feb. 17 and the New York Spectator on March 3 reported snow in Norfolk "in many places up to six feet deep," the greatest snowfall ever experienced. Some accounts claim that 40 inches of snow fell in one night in Norfolk and along the coast, but no snow fell 25 miles inland. Over northeast North Carolina, 16 inches of snow was reported. Wind blowing from the north to northwest off the Chesapeake Bay may have enhanced the snowfall in the Norfolk area, much like the winds blowing across Lake Erie produce "lake effect snow" in New York.