The weather records of Rev. Dr. Michael Jacobs of Pennsylvania (now Gettysburg) College were cited in a July 4 blog post for 22 News in Western Massachusetts.
From 22 News:
Weather & the Battle of Gettysburg
Historical battles – we often think of the events that happened and the people involved. But, how often do we think about the weather?
149 years ago, July 3,1863, the Battle of Gettysburg ended. It was one of the largest battles ever fought in America. In total, there were over 51,000 casualties. Even though you may not think about it, the weather affected those who fought.
Rev. Dr. Michael Jacobs, who taught at Pennsylvania College as a Professor of Mathematics and Science, recorded temperatures and sky conditions during the Battle of Gettysburg. He recorded conditions at 7 AM, 2 PM, and 9 PM.
On July 1st, (the first day of the battle) Jacobs recorded temperatures in the mid-70s at 2 PM. He recorded that it was cloudy most of the day – with cumulostratus, cirrostratus clouds, and a light warm breeze. He said the entire sky was covered by clouds, but since cumulostratus and cirrostratus clouds tend to be thin, we can assume there might have been some sunshine peaking through the overcast sky.