The Weather Watch
Washington's preoccupation with the weather was clearly an extension of his needs and interests as a farmer.
Washington's preoccupation with the weather was clearly an extension of his needs and interests as a farmer. He was not a scientific observer, as was Jefferson, and his weather records are irregular in scope and content. In editing the diaries for the 1925 edition, Fitzpatrick abandoned the weather record midway in his first volume except when it could not be sorted from other matters recorded, calling the weather entries "unessential" (John C. Fitzpatrick, ed., The Diaries of George Washington, 1748-1799 [4 vols.; Boston and New York, 1925], 1:288n). Our view is that because we cannot and should not attempt to predict the use which readers will be making of the diaries, the weather material should remain. Records for the study of eighteenth-century meteorology are not so plentiful that Washington's may be ignored.
It is difficult to separate him from the weather because so much Washington lore is weather-connected. Seasick days during a stormy voyage to Barbados; the cruel winters at Valley Forge and Morristown; the dust and mud of carriage roads during a lifetime of travel; and, at least in the minds of his family and friends, the probability that an ill-advised horseback ride in a December storm contributed to his death.
His instruments for recording the weather were few, but one in particular is notable. His prized weather vane has survived the changing winds and still serves atop the cupola at Mount Vernon. The vane is in the shape of a dove of peace, the copper body bound with iron strips and the bill with olive branch fashioned from a piece of iron. The bird is forty inches long, and the wing from tip to tip measures thirty-five inches. The vane was made in Philadelphia, by Joseph Rakestraw, in July or Aug. 1787, and was sent immediately to Mount Vernon. Washington wrote his nephew George Augustine Washington, 12 Aug. 1787, that the bill of the dove was to be painted black and the olive branch green. This color scheme is no longer maintained today, the vane having been covered with gold leaf to deter corrosion of the copper body.
Washington made no attempt to measure barometric pressure (though he mentions "falling weather" now and then), and his references to humidity are subjective assessments, not readings from an instrument. Aside from the weather vane, his only known weather instrument was the thermometer. Writing to farm manager William Pearce, from Philadelphia 22 Dec. 1793, he said, "And as it is not only satisfactory, but may be of real utility to know the state of the weather as to heat & cold, but drought or moisture, prefix, as usual, at the head of every weeks report a meteorological account of these. The Thermomiter which is at Mount Vernon will enable you to do the first" (Long Island Historical Society, Brooklyn, New York).
Two barometer-thermometers now at Mount Vernon, one in Washington's study and the other in the central hall of the mansion, are connected with Washington by family tradition only. A third instrument is probably one mentioned in an inventory of his effects not long after his death. While the inventory accords it a place in the Washingtons' bedroom, where it hangs today in restored form, it may have been located originally in the east hall outside the study. It is a registering thermometer designed to record high and low temperatures for the day, and bears the name of Joseph Gatty, a New York instrument maker.
One of Washington's comments about temperature leads to the speculation that at least some of his readings were made inside the mansion house. "Thermometer at 52 in the Morning & 59 at Noon," he writes in the diary on 7 Dec. 1785, "but removing it afterwards out of the room where the fire was, into the East Entry leading in to my Study, this circumstance with the encrease of the cold fell the Mercury to 42." Meteorologists might charge that Washington was ill advised if not actually foolish for recording indoor readings, and certainly such readings would be of little use today in studying eighteenth-century weather. And ill advised he may have been, by Dr. James Jurin, secretary of the Royal Society of London. Publishing a set of recommendations for keeping a meteorological register, Jurin advocated placing the thermometer "in a room which faces the north, where there is very seldom if ever any fire in the fireplace" (Royal Society, Philosophical Transactions, 32 , 425).
In Europe, Jurin's fellow scientists objected to this recommendation, but in English-speaking countries the practice continued through the end of the century. New York and Philadelphia scientists carried on a debate about the practice of thermometer location, and at least one Philadelphia record carries one column for indoor and another for outdoor readings. Jefferson, however, was not a disciple of Jurin. When he discovered that his thermometer in the northeast portico was being affected by an unknown source of heat, perhaps a mound of earth, he changed its location and rejected eighteen months of readings in his weather record (weather diary, Massachusetts Historical Society, Boston; transcript, University of Virginia, Charlottesville). For a brief discussion of early views on the correct location of the thermometer, see W. E. Knowles Middleton, A History of the Thermometer and Its Use in Meteorology (Baltimore, 1966), 208-13.
Washington's temperature records begin Jan. 1785. It may never be possible to determine which readings were made indoors and which outdoors, although there are hints in the records themselves. In 1785, during a period when he was recording three readings daily--morning, noon, and sunset--there is very little variation in the day's temperature from reading to reading. For example, on 19 Jan. he records a reading of 48° Fahrenheit in the morning, 48° at noon, and 48° at sunset. On occasion there seems to be a discrepancy between his temperatures and what he says the weather is doing. He wrote on 26 May that the weather was warm until about 5:00 P. M. when clouds and high wind brought about a marked change in the temperature of the air. Yet his three readings for the day are 65°, 68°, and 67°.
Some of his extremely cold readings may indicate that the thermometer was outdoors. He wrote on 5 Feb. 1788 of weather so cold that the mercury did not rise out of the bulb of the thermometer all day. But he was writing about one of the coldest days of the century, when near Philadelphia the temperature registered--17° F.
If he was not scientifically accurate, he was at least persistent. See his entry for 30 April 1785 when, unable to record the weather personally because of a trip to Richmond, he had put Mrs. Washington in charge of the thermometer. "Mercury (by Mrs. W's acct.) in the Morning at 68--at Noon 69 and at Night 62." Even on great occasions in his life, the weather was on his mind. On 9 Mar. 1797 he left Philadelphia for the last time, after a lifetime of public service in which he longed always to return to Mount Vernon. "Wind changed to No. Wt. blew very hard & turned very cold," he wrote in his diary. "Mer. at 28. Left Phila. on my return to Mt. Vernon--dined at Chester & lodged at Wilmington."