A Visitor's Guide to Colonial & Revolutionary Mid-Atlantic America
Washington’s weather in 1776
“The Delaware crossing became the third stroke of good fortune that partially salvaged an otherwise dismal year of defeats for Washington. Success in all three depended upon a familiar storm pattern on the East Coast—the three-day nor’easter. In March Washington had succeeded in getting the guns Henry Knox had dragged all the way from Ticonderoga to Dorchester Heights, where they commanded the British position in Boston. General Howe ordered an attack on the heights and began to send troops in transports when a fierce nor’easter set in and scattered the operation; the next day, with the storm still raging, Howe decided to evacuate Boston.
Again, at the end of August when Washington had lost the Battle of Long Island to General Howe’s overwhelming forces and was trapped at Brooklyn Heights, he was in danger of losing the entire Continental Army and perhaps the war. When a strong nor’easter set in, it was his turn to evacuate—under its cover, if the timing was right. The same strong northeast winds that kept the British fleet from beating up into the East River to block his escape made the crossing to Manhattan too rough to get boats loaded with troops across. But when that wind died about 11 o’clock on the night of August 29 and was replaced by moderate breeze from the southwest, Washington was able to start his mass evacuation, but not complete it before dawn. Then came the final stroke of luck that would continue his concealment: a thick fog that did not lift until his last boats reached Manhattan about 7 am.
So the nor’easter that provided cover for the crossing to attack Trenton rounded out a year when the weather seemed to take sides for the Americans at three crucial moments.”