Blue Hill Observatory: The Oldest Weather Record in the Western Hemisphere

Ten miles south of Boston, atop a drumlin called Great Blue Hill in the town of Milton, there is a stone tower that has been measuring the weather every day without interruption since February first, eighteen eighty-five. That is the longest continuous weather record in the Western Hemisphere.

The man who built it was Abbott Lawrence Rotch, twenty-three years old and newly trained at MIT, the heir to a Boston Brahmin fortune who decided to spend it on the atmosphere. He commissioned the stone tower in eighteen eighty-four and started observations on February first, eighteen eighty-five. He never stopped.

Rotch and his observers pioneered the use of kites to carry instruments into the sky, among the earliest soundings of the upper atmosphere ever attempted in North America. In the nineteen thirties, researchers at Blue Hill helped develop the radiosonde, the battery-powered instrument package carried aloft by weather balloons that meteorologists still use today.

The observatory's most dramatic data point came on September twenty-first, nineteen thirty-eight, when the Great New England Hurricane churned up the coast. At six in the afternoon, as the storm passed directly over the summit, an observer inside recorded a wind gust of one hundred eighty-six miles per hour. It remains the highest wind speed ever directly measured and recorded in a hurricane in the United States. The back windows of the observatory blew out while the reading was being taken.

The World Meteorological Organization designated Blue Hill as a Centennial Observation Station in twenty seventeen, recognizing it as one of the most scientifically significant long-term climate records on Earth. The tower still staffs human observers around the clock, one of the last stations in the country that does.