An unexplained darkness that fell at midday, making stars visible. Theories include massive fires but no source has been definitively identified.
Rigobert Bonne, Public domain, via Wikimedia Commons
A sky of midnight at noon
On the morning of May 19, 1780, the sun rose over New England, but it was an unusual red and emitted little light. By 10:30 a.m. in Cambridge, Massachusetts, the sky had grown so dark that it alarmed professors at Harvard College. The obscuration spread over the New England states and parts of eastern Canada, extending as far south as New Jersey.
Eyewitnesses described a yellowing sky that transitioned to complete darkness by noon, requiring candles for any indoor activity. The darkness was so deep that a piece of white paper held inches from the eyes was as invisible as black velvet. Animals reacted with confusion; chickens returned to their roosts, frogs began their evening chorus, and cattle headed back to their stalls. Rainwater collected during the event had a sooty smell and a visible film of burnt leaf particles and ash. In parts of New Hampshire, ash and cinders reportedly fell to a depth of six inches. The bizarre phenomenon did not disperse until the middle of the following night.
The wildfire hypothesis
For over two centuries, the cause of the Dark Day remained a mystery, with theories ranging from a solar eclipse to volcanic eruption. Modern science points to a natural cause: smoke from massive forest fires. Researchers at the University of Missouri's Tree Ring Laboratory analyzed tree cores from the Algonquin Highlands in Ontario, Canada.
The tree rings show distinct "fire scars" for the year 1780. These scars form when the heat from a wildfire kills a portion of the tree's living tissue, leaving a mark in the growth ring. This dendrochronological evidence indicates that a large-scale fire occurred in that region just before the Dark Day.
The scientific model suggests that immense columns of thick smoke from these Canadian fires were carried into the upper atmosphere. A combination of specific weather conditions—thick fog and low cloud cover over New England—trapped this dense smoke close to the ground, blocking sunlight for an extended period. This explains the sooty rain, the smell of burning material, and the geographic extent of the darkness.
💡Fun Facts
In Hartford, the Connecticut legislature was in session and, fearing Judgment Day, some members called to adjourn. Councilman Abraham Davenport famously retorted, "The day of judgment is either approaching, or it is not... I wish therefore that candles may be brought."
The darkness was so disorienting that nocturnal birds like the whip-poor-will began their serenade in the middle of the day.
General George Washington, then stationed with the Continental Army in New Jersey, recorded the "dark and at the same time a bright and reddish kind of light" in his diary.
When the moon finally became visible late that night, it appeared to be blood-red, further alarming the populace.
