 Historical weather on this day, June 28, 1778. The Battle of Monmouth happened on this day in 1778 in central New Jersey. The Battle of Monmouth was part of the American Revolutionary War and saw the Continental Army commanded by George Washington go against the British Army. Interesting weather fact about that particular battle, however, was the fact that most of the casualties came not from the fighting, but from none other than intense heat that day. It was in the mid to upper 90s in central New Jersey as the battle occurred. Historical weather on this day is a production of Monsoon Mike's Weather.