Remembering the Battle . . . and the Weather

As Gettysburg National Military Park commemorates the 150th anniversary of the momentous and bloody battle fought there (it took place July 1-3, 1863), we can look back and examine the role weather played in those three days of conflict (and AccuWeather already has, in this interesting post). This is possible thanks in large part to a local man, Rev. Dr. Michael Jacobs, who took weather observations three times a day, even as the fighting raged on around him. His notes, which can be seen here, show that temperatures were slightly below average for all three days, and that cloud cover was considerate much of the time. This benefited the soldiers, who would have been most uncomfortable in their wool uniforms during extreme heat and/or humidity. Late on July 3, a thunderstorm broke out, and it is testament to the ferocity of the battle that Jacobs noted the thunder “seemed tame” after the nonstop cacophony of gunfire that echoed throughout that afternoon.
As the battle wound down, the weather intensified, with rain falling throughout the day (a total of 1.39 inches, according to Jacobs) on July 4, the day after the combat had ended. The inclement weather turned out to be significant, as some wounded soldiers were still lying on the battlefield; tragically, those who were in low-lying areas drowned when the rainfall caused the Plum Run Creek to overrun its banks. The rains also added insult to injury for the retreating Confederate army–the dirt roads they traveled on rapidly became treacherous, and as they moved southward they were trapped for a period of time on the north side of the Potomac after the river swelled, making it temporarily impassible. They weren’t able to cross until July 13th.