O '''Dia Escuro''', também conhecido como '''Dia Escuro da Nova Inglaterra''', refere-se a um evento ocorrido no dia [[19 de maio]] de [[19701740]], quando os céus da [[Nova Inglaterra]] e de partes do [[Canadá]] ficaram demasiadamente escuros apesar do horário.<ref>{{cite news |title = Ten Notable Apocalypses that (Obviously) Didn’t Happen|url = http://www.smithsonianmag.com/history-archaeology/Ten-Notable-Apocalypses-That-Obviously-Didnt-Happen.html|quote = At 9 am on May 19, 1780, the sky over New England was enveloped in darkness. An 1881 article in Harper’s Magazine stated that, “Birds went to roost, cocks crowed at mid-day as at midnight, and the animals were plainly terrified.” The unnatural gloom is believed to have been caused by smoke from forest fires, possibly coupled with heavy fog. But at the time, some feared the worst. 'People [came] out wringing their hands and howling, the Day of Judgment is come,' recalled a Revolutionary War fifer. ...|work = [[Smithsonian magazine]]|date = November 12, 2009|accessdate = November 14, 2009}}</ref> A causa principal para isso pode ter sido uma combinação de [[Fumo|fumaça ]]de [[Incêndio florestal|incêndios florestais]],<ref name="Ross">{{cite journal |url = http://www.americanheritage.com/articles/magazine/ah/2008/5/2008_5_8_dept.shtml|first = John|last = Ross|title = Dark Day of 1780|journal = American Heritage|date = Fall 2008}}</ref> uma espessa [[Nevoeiro|neblina]] e céu encoberto. A escuridão foi tamanha que [[Vela]]s foram necessárias durante o dia. O fenômeno não dispersou até metade da noite seguinte.<ref name="almanac">{{cite book |chapter = New England's Dark Day|title = The Weather Doctor Almanac|year = 2004|chapter-url = http://www.islandnet.com/~see/weather/almanac/arc2004/alm04may.htm}}</ref><ref name="account-p519">{{cite book |chapter = An Account of a Very Uncommon Darkness, in the State of New England, May 19, 1780|title = The Analytical Review, Or History of Literature, Domestic and Foreign, on an Enlarged Plan|page = 519}}</ref>
Segundo o professor Samuel Williams da Faculdade de Harvard, a escuridão foi vista ao menos entre [[Portland (Maine)|Portland, Maine]] ao norte e [[Nova Jérsia]] ao sul, mas não chegou a ser vista na [[Pensilvânia]].<ref name="almanac">{{cite book |chapter = New England's Dark Day|title = The Weather Doctor Almanac|year = 2004|chapter-url = http://www.islandnet.com/~see/weather/almanac/arc2004/alm04may.htm}}</ref>
