气象人(Weatherman)，全名为地下气象人组织（Weather Underground Organization，简称WUO），是美国的一个极左派组织，1969年由反越战组织民主社会学生会（Students for a Democratic Society）中的激进派分裂出来。他们的目标是以秘密、暴力、革命推翻美国政府。

他们反对种族歧视(尤其是白人对于黑人的不公义对待)，以及反对越战，并认为惟有把战争也带到美国本土上，才能让美国人知道自己的政府在国外犯下的罪刑。在纪录片《地下气象人(Weather Underground)》中可以得知，当时的成员认为「在一个暴力的时代，看着你的国家在别人的土地屠杀无辜的人民，如果什么也不做，只是继续享受你的中产阶级舒适，这本身就是一种暴力的行动」。

The Weather Underground Organization (WUO), commonly known as the Weather Underground, was an American militant radical left-wing organization founded on the Ann Arbor campus of the University of Michigan. Originally called Weatherman, the group became known colloquially as the Weathermen. Weatherman organized in 1969 as a faction of Students for a Democratic Society (SDS) composed for the most part of the national office leadership of SDS and their supporters. Their goal was to create a clandestine revolutionary party for the overthrow of the U.S. government.