July 4, 1776: a Look at Philadelphia's Historic Weather

WHO:

Forbes - Thomas Jefferson kept meticulous weather records over several decades.

Forbes - The National Weather Service (NWS) issued warnings regarding extreme heat.

WHAT:

NY Post - Philadelphia was a breezy 76 degrees on July 4, 1776.

Forbes - Philadelphia tied a maximum temperature record with a reading of 103 degrees Fahrenheit.

Forbes - The NWS warned of dangerously hot conditions with maximum heat index values between 105 and 110 degrees.

Forbes - There is a 30% chance of afternoon thunderstorms on July 4, 2026.

WHERE:

NY Post - The events took place in Philadelphia, Pennsylvania.

Forbes - The Great American State Fair was held in Washington D.C.

Forbes - The NWS issued warnings for the Philadelphia area.

WHEN:

Forbes - The signing of the Declaration of Independence occurred on July 4, 1776.

Forbes - July 4, 2026, is noted for extreme heat and the cancellation of events.

Forbes - The NWS issued an extreme heat warning until 8 pm on July 4, 2026.

WHY:

Forbes - A massive heat dome has gripped much of the eastern United States, causing extreme temperatures.

Forbes - Heat-related illnesses increase significantly during extreme heat and high humidity events.

HOW:

Forbes - The NWS provided warnings and information regarding the heat conditions and their potential impacts.

(UPDATED July 4, 2026 23:15 UTC)

In Philadelphia, the National Weather Service has issued warnings about extreme heat, with maximum temperatures reaching a record 103 degrees Fahrenheit and heat index values soaring between 105 and 110 degrees. This intense heat is attributed to a massive heat dome affecting much of the eastern United States, raising concerns about heat-related illnesses. Looking ahead, there is a 30% chance of afternoon thunderstorms on July 4, 2026, as the city braces for the sweltering conditions.