Blue Hill Meteorological Observatory

The Blue Hill Meteorological Observatory, also known as Great Blue Hill Weather Observatory, Blue Hill Weather Observatory, or simply the Blue Hill Observatory, in Milton, Massachusetts is the foremost structure associated with the history of weather observations in the United States. Located atop Great Blue Hill at the junction of Interstate and Route about 10 miles (16 km) south of Boston, Massachusetts, it is home to the oldest continuous weather record in North America, and was the location of the earliest kite soundings of the atmosphere in North America in the 1890s, as well as the development of the radiosonde in the 1930s.

Founded by Abbott Lawrence Rotch in 1884, the observatory took a leading role in the newly emerging science of meteorology and was the scene of many of the first scientific measurements of upper atmosphere weather conditions, using kites to carry weather instruments aloft. Knowledge of wind velocities, air temperature and relative humidity at various levels came into use as vital elements in weather prediction due to techniques developed at this site. By 1895 the observatory was the source of weather forecasts of remarkable accuracy. During the Great New England Hurricane of 1938, the observatory measured the strongest wind gust ever recorded in a hurricane at 186 mph (299 km/h).

The observatory remains active to this day, continuing to add to its data base of weather observations now more than one hundred years old, and stands as a monument to the science of meteorology in the United States.