U.S. Independence Day, smack dab in the middle of summer, is often a hot day for most Americans. Many people head to the beach, mountains, pools and lakes to cool off and spend time cooking hamburger and hot dogs on the grill. What you might not realize is that July 4, 1776, was an unseasonably mild mid-summer day in usually hot and humid Philadelphia.

Thomas Jefferson, one of the country's founding fathers and its third president, kept an extensive weather journal throughout his life. In his journal entry for July 4, 1776, he observed a 68-degree temperature at 6 a.m., 72-degree reading at 9 a.m. and a 76-degree reading at 1 p.m.

Another Philadelphian, Phineas Pemberton recorded similar temperatures as well as increasing afternoon clouds, a decreasing barometric pressure and a wind shift from the north to the southwest on that famous day.

Compared to modern temperature records, the 1776 high temperature of about 76 degrees is 9 degrees cooler than the 85 degree normal the city of Brotherly Love experiences. So when you think to colonial days, remember that our founding fathers had a nice day, weather wise, to declare the nation's independence.

Image: John Trumbull's painting, Declaration of Independence. The original hangs in the U.S. Capitol Rotunda. (Wikipedia)

July 4, 1776 - An Unseasonably Mild Day in Philadelphia