The current October snowfall in the northeastern U.S. has certainly been impressive, particularly in the areal extent, but the historical record shows that autumn snowstorms were both earlier and more frequent in the mid-19th century. In his definitive history, "Early American Winters", David Ludlum lists records of early season snowfalls in 21 of the 50 years from 1821 to 1870, including many in September and several in late
August. The mid-1830's were particularly prolific, with 3 events before the middle of October in 1836, including at least "some snow" as far south as South Carolina.
1821: Oct. 25-26, Salem MA: "sufficient to cover the ground"
1823: Sept. 29, Worcester County MA: "snow in several parts of the county"
1829: Sept. 3, Sherburne VT: "an inch and a half deep"
1832: Aug. 25-26, New Hampshire: "White Mountains covered by snow apparently several inches deep"
1833: Oct. 30, Somerset PA: "Two inches snow, the fourth fall of the autumn"
Oct. 29-30, Philadelphia PA: "Houses whitened by snow"
1835: Sept. 30, northern New England: 6-12" in Franklin County, Vermont; 6" at Kilkenny New Hampshire
1836: Sept. 28: Hamilton NY 4", Bridgewater NY 3", Rochester NY 1"
October 5-6: Onondaga County NY 2 feet, Auburn NY 24-26" Cortland NY 18", Hollidaysburg PA 26", Sideling Hills MD 10", Loudoun County VA 5", Yorkville SC "some snow"
October 11-12: Hamilton NY 35" "measured as it fell", Madison NY 12", Bridgewater NY 18", Oxford NY 12"
[More reports to be added later]