The United States Weather Bureau was created on February 9th 1870, because Civil War Generals wanted accurate forecasts for battles.
A joint resolution of Congress established the United States Weather Bureau. The task of the Bureau was to "provide for taking meteorological observations at the military stations in the interior of the continent and at other points in the States and Territories...and for giving notice on the northern (Great) Lakes and on the seacoast by magnetic telegraph and marine signals, of the approach and force of storms." It was signed into being by United States President Ulysses S Grant on February 9th 1870.
The Bureau was placed within the Department of War. The Secretary of War had the Bureau assigned to the United States Army Signal Corps which was commanded by Brigadier General Albert J Myer. The first weather observations were made at 22 stations, with the information gathered 3 times a day telegraphed to Washington, DC, where 4 “professionals” would issue a forecast.