The Missoula office of the U.S. Weather Bureau was established on November 1, 1935, in the Montana Building at 101 Broadway. On November 1, 1938, the office moved one block to the Federal Building. From July 1, 1939, to October 1, 1941, weather observations were also recorded by Civil Aeronautics Administration personnel at Hale Field; this station moved to the Missoula County Airport effective October 1, 1941. The two weather stations were consolidated when the Weather Bureau office moved to the Missoula County Airport on December 1, 1944.
The Weather Bureau was established in 1870. It was under the authority of the Army Signal Service/Signal Corps until 1891, when it was transferred to the U.S. Department of Agriculture. In 1940 the Weather Bureau was transferred to the U.S. Department of Commerce.
In Missoula, before establishment of the Weather Bureau office, weather observations were made by the U.S. Army at Fort Missoula from April 1893 to May 1898. From May 1898 to November 1935, weather observations were made by University of Montana Professor Morton J. Elrod and his students at his home on West Fifth Street South in Missoula.
From the guide to the Missoula Weather Forecast Office Records, 1935-1988, (Maureen and Mike Mansfield Library Archives and Special Collections)