Pennsylvania College (now Gettysburg College) Prof. Michael Jacobs' weather notes from the Battle of Gettysburg were mentioned in a June 29 Baltimore Sun article.
From the Sun:
Curious about the weather during the Battle of Gettysburg fought by soldiers in wool uniforms July 1-3, 1863? The Rev. Dr. Michael Jacobs, a math and science professor at Pennsylvania College, now Gettysburg College, recorded the temperatures three times a day during the battle: 7 a.m., 2 p.m., and 9 p.m. On July 1 the temperature at 2 p.m. was 76 degrees and the sky was cloudy. At 2 p.m. July 2, it was 81 and partly cloudy. It was 87 degrees at 2 p.m. July 3, the time of Pickett's Charge. Lee's retreat from Gettysburg on July 4 was hampered by rain, mud and swollen creeks. The thousands who will gather in Gettysburg for re-enactments next week will see temperatures in low to mid-80s and scattered thunderstorms predicted most days.