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How George Washington’s used his weather knowledge during the American Revolution

The Declaration of Independence was signed in the warmth of a Philadelphia summer. But 240 years ago, as 1776 came to a close, it appeared the Revolution might be doomed. George Washington and his forces had suffered a string of losses, and with each loss, there was less and less public support. After all, if the Revolution was lost and the British won, all who participated or aided in the revolt could be tried and convicted of treason against the Crown.

Washington and his depleted forces dared to cross the icy Delaware River on Christmas night, then cunningly circled around and attacked Trenton from the north with the winds at their backs. The sleepy-eyed Hessian defenders waking up on the morning after Christmas were greeted by stinging sleet and a hail of bullets from the Americans who could hardly be seen through the storm.

The stunning victory at Trenton proved to be the turnaround event that fueled the rebel fire once again, but that was far from obvious as Washington and his forces re-crossed the river and regrouped. The army was about to dwindle away. Enlistments were up at the stroke of midnight, New Year’s Eve. Desperate, and without official authorization, Washington called on the soldiers to stay, offering them a bonus if they extended their enlistments. The soldiers did not respond at first, but then one stepped forward, then another and then another.

They hatched a plan to attack the British once again. Meanwhile, the snow on the ground melted. The rebels crossed the Delaware again on New Year’s Day. This time the British were ready, and the rebels were forced into a corner. They were stranded in muddy fields, back to the river, with no way to escape.

But Washington was a Virginia farmer; he watched the weather. He had experienced winter days with blue skies and northwest winds, where the temperature would hold steady during the day then sink below freezing at night. The stiff northwest wind had erased the 50 degree weather of the previous day. Washington’s thermometer read 39 degrees and holding at noon. Washington ordered the troops to prepare huge bonfires after sundown and make the appearance of bustling around in the camp.

Behind the fire glow, it was dark — the dark that we rarely experience in this age of light pollution. Washington’s troops readied their equipment, even wrapping wagon wheels in cloth to minimize the noise. The ground froze. The forces moved out, picking their way northward, away from the encamped British who were lying in wait to mount their own attack at first light.

Dawn broke to the sight of rebel soldiers marching toward Princeton through fields laced with frost. The Battle of Princeton was fierce, but lasted less than an hour. The British were defeated again and pulled back to their garrisons farther northeast in New Jersey. News of the rebel victories spread like wildfire back in Europe weeks later. Soon the French would be emboldened to declare war on Britain and help the American cause. If Washington had not realized that it would freeze at night, his forces would have been surrounded and captured the next day.

OLLI at Penn State — open to adults who love to learn — will be offering more than 130 courses this spring. Past semesters have included sessions such as “How George Washington’s Weather Knowledge Helped during the American Revolution,” led by Elliot Abrams. To receive a free spring semester catalog, call OLLI at Penn State at 867-4278 or visit

Elliot Abrams is a senior vice president and chief forecaster for AccuWeather.