On May 19, 1780, in the northeastern part of North America, there was a period of "extraordinary darkness," which began between 10 A.M. and 11 A.M. and lasted until the middle of the next night. Also, the full moon rose at 9 P.M. that evening but was not visible until midnight, when it had the "appearance of blood." Records of solar and lunar eclipses for that date, indicate none was close enough to have caused the phenomenon.

For a generation of New Englanders, Friday, May 19, 1780, was a date never to be forgotten. The Sun was blotted out by a strange darkness, varying in intensity and length from place to place, but extending from New Jersey and New York across Connecticut, Rhode Island, Massachusetts, and southeastern New Hampshire into Maine. For several days prior to the "Dark Day," the Sun was obscured by smoky clouds, and the Moon took on an unusual reddish color. Darkness began around 10 in the morning and lasted throughout the day. (When the Connecticut legislature proposed adjournment following the belief that the day of judgment was at hand, a Colonel Davenport declared: "I am against an adjournment. The day of judgment is either approaching, or it is not. If it is not, there is no cause for an adjournment; if it is, I choose to be found doing my duty.") The night that followed was no comfort to the fearful, being unusually black and impervious to any artificial light. The next day, a fine sulfurlike substance was noticed on the edges of water, but the only reports of adverse effects concerned the death of a number of birds. The first theories of a comet or solar eclipse were ruled out, and the earliest guesses regarding smoke from forest fires turned out to be accurate. Out-of-control forest fires, extending from New Hampshire into New York State, burned furiously for a week preceding the dark day, creating great suffocating clouds of smoke. An unusual atmospheric condition trapped the smoke until it reached sufficient density to blot out the Sun. However, for many New Englanders, the Dark Day was an inexplicable mystery, never recalled without a feeling of awe.