Julius Ferdinand von Hann (23 March 1839 in Wartberg ob der Aist near Linz – 1 October 1921 in Vienna) was an Austrian meteorologist.

He was educated at the gymnasium of Kremsmünster and then studied mathematics, chemistry and physics at the University of Vienna, then geology and paleontology under Eduard Suess and physical geography under Friedrich Simony.

From 1865 to 1868, he was master at the Oberrealschule at Linz, and in 1865 was invited by Karl Jelinek to become the first editor of the Zeitschrift für Meteorologie.

He became an international honorary member of the American Academy of Arts and Sciences in 1902.

[1] In 1912, he was made a foreign knight of the Prussian Ordre Pour le Mérite.