The Fourth of July is a day for coming together to celebrate our nation’s birthday! However, some may remember it for the historical weather events that have taken place.
Thomas Jefferson and his most famous thermometer
Thomas Jefferson may be the most famous and first amateur meteorologist in the United States. He’s noted for keeping a weather diary for most of his life, but did you know he started a more detailed, daily recording of temperatures and other notable weather on July 1, 1776!
To keep accurate readings, he purchased 20 different thermometers. However, the most famous of those was purchased on July 4, 1776, the same day the Declaration of Independence was adopted by the Continental Congress! He purchased the thermometer from a Philadelphia merchant named John Sparhawk for a little over three British pounds. Adjusting for inflation and converting to U.S. dollars today, that thermometer would be $850!
His thermometers and daily temperature readings would stand the test of time, giving us a glimpse of weather and climate (Jefferson also included the timing of blooming plants and the migration of animals) in the early days of our country.
A portion of Thomas Jefferson’s weather observations from 1776. A more comprehensive diary kept track of daily highs, lows and other weather information. (climate.gov)
Talk about raining on our parade
When we plan our Fourth of July festivities, the number one question is, “Will it rain?” It makes pool time, parades and ultimately fireworks tougher to navigate. All of that makes this notable weather event hard to imagine.
On July 4, 1956, a thunderstorm over Unionville, Maryland, dumped a record-breaking amount of rain. In just one minute, 1.23″ of rain came down, setting a Guinness Book of World Records mark that still stands today. That amount of rain in one minute would equate to about 74 inches of rain in an hour.
Compare that to some other rainfall records like the highest 1-hour rainfall (12″ in Holt, Missouri on June 22, 1947) and 12-hour rainfall (45″ in Foc-Foc, La Réunion in the Indian Ocean during Tropical Cyclone Denise in 1966), and that amount of rain in just one minute is very impressive and probably will never be topped.
Hotter than a firecracker
We can’t discuss July Fourth weather without mentioning the oppressive heat that can build this time of year. The hottest temperatures ever recorded on July Fourth in the U.S. was in Death Valley, CA fairly recently in 2024. The mercury climbed to almost 128°! And if you didn’t know, Death Valley also holds the record for the hottest air temperatures ever recorded on Earth, climbing to 134° on July 10, 1913.
In the cradle of American history, the Northeast U.S., a notable heatwave set temperature records on July 4, 1911, many of which still stand today.
Nashua, New Hampshire saw the thermometer climb to 106°, while just down the road, temperatures surged to 105° in Vernon, Vermont and North Bridgton, Maine. These aren’t just records for July 4th, but all-time hottest temperatures ever for these New England states.
In Boston, the Fourth of July high hit 104°, and Albany, New York, and Portland, Maine, checked in at 103°. All these were all-time records for those spots.
Many of us should prepare for intense heat this Fourth of July, as we may get close to setting records for America’s 250th birthday. Make sure you hydrate, take frequent breaks in the AC and shade, and take care of the little ones and elderly, as they are the most vulnerable to the heat.
We hope everyone stays safe and healthy as we celebrate this year!
Our team of meteorologists dives deep into the science of weather and breaks down timely weather data and information. To view more weather and climate stories, check out our weather blogs section.
Spectrum News Weather Staff
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