When delegates gathered in Philadelphia on July 4, 1776, to approve the final wording of the Declaration of Independence, there were no satellites or radar to track the weather, but fortunately, a man by the name of Thomas Jefferson, along with other colonial-era observers, recorded what the weather conditions were like.
According to logs compiled by Jefferson, Independence Day in Philadelphia was a relatively cool affair, with a low around 68 degrees and a high of just 76 degrees. Because no sky observations were noted by the future-president, it was likely a mostly clear day across the colony.
A recreation of the synoptic weather map depicts a ridge of high pressure settled over the western Atlantic, while a cold front with an associated area of low-pressure stretched from the Great Lakes through the heart of what was then controlled by the Spanish Empire.
Unfortunately, there is little documentation of the weather across the modern-day Sunshine State, which is not unusual because inhabitants were living through a transition period from Spanish occupation to British control.
Spain had controlled the Florida territory from the days of Juan Ponce de León in 1513 until 1763, when the territory was ceded as a result of the conclusion of the Seven Years' War.
According to historians, Britain invested resources into the territory, but that effort did not involve taking widespread weather observations.
Fortunately, the British hired a surveyor named Bernard Romans who, in his journals, in addition to detailing the landscape, occasionally dabbled in documenting the weather conditions.
While Romans was not in Florida when the Declaration of Independence was signed, his previous accounts of summers provide some of the most vivid descriptions of the time.
"The atmosphere is, during this season, so burning hot, that undoubtedly very sudden rarefactions of the humours are often experienced, which cause such abundant perspiration, that water, as soon as drank, penetrates the open pores, so that the human skin seems to be comparable to a wet sponge when squeezed," Romans stated in his concise natural history of East and West Florida.
Based on the continent's synoptic picture, forecasters can surmise what the weather setup was likely like back on July 4, 1776.
A present-day typical low temperature in Florida on July 4 is about 74 degrees, while the average high is around 92 degrees.
But 250 years ago, there was less concrete around and more undisturbed swampland - a combination of ingredients that would have altered what a summer day was like.
Climate Central, a nonprofit organization that reports on climate and its impacts, suggests through its research that temperatures were at least 2.2 degrees cooler back then.
That means if a normal day's weather occurred on July 4, 1776, temperatures would have been in the upper 80s, but this does not take the humidity into account.
With humidity values between 70% and 100%, the air temperature would have felt in the range of 100 to 121 degrees - not too much different than recent Independence Days.
Again, without a firsthand account from someone who lived through the period, the best forecasters can do is only infer what the weather was likely like.
A more stable governmental period in Florida's history emerged when Spain retook the territory from 1783 to 1821, leading to increased weather reports.
The territory was not ceded to the United States until 1821, and it did not become a state until 1845.
The first official weather office in Florida did not open until 1870 in Key West, where it operated under the command of the U.S. Army.
Today, the Sunshine State is home to six National Weather Service offices that fall under the jurisdiction of the U.S. Department of Commerce.
