A radical Leninist-Marxist Communist group in America that was an offshoot of the anti-war effort in the '60s. They began by participating in non-violent anti-war protests, such as the 1969 Love-In and the sit-ins at Berkeley, Columbia, and many other universities. They were mostly upper-middle class college kids, but through the anti-war movement, as well as the opposition to it, they became progressively more radical.

Identifying themselves as Leninist-Marxist, the Weathermen got their name from a Bob Dylan song, where a line states that "You don't need a weatherman to know which way the wind's blowing." The Weathermen were based out of Greenwich Villiage. When their townhouse (owned by one of the member's capitalist parents) accidentally exploded during one of the many Columbia protests in 1969, the members went underground, many fleeing to Canada.

In 1970, the Weathermen published their manifesto, purporting two main goals that any Leninist-Marxist of good conscience living in America (the bastion of capitalism) would be striving for to ensure succes of the movement.

The first of these was to support the burgeoning Black Power movement (even and especially the more violent of these actions). This was because the Weathermen, much like many other communist or socialist groups of the '60s and '70s, recognized that the workers were not the most likely place to look for revolution. They recognized that the only group that was both large enough in numbers to be significant and that had been oppressed so much and so systematically that they had nothing to lose would be the African-American community. Therefore, supporting Black Power movements would encourage African-Americans to recognize and get pissed off about their subjugation, while also helping them organize.

The other action that any "self-respecting" Communist would take is to use any measures necessary to ensure the United States' losing the Vietnam War. The Weathermen also recognized that helping Communism spread in places such as Vietnam was beneficial toward supporting a global Communist influence.

The Weathermen were not, at base, a violent group of dissenters. They were clearly dissenting with the popular opinion, but violence was something that was utilized only occasionally and (usually) somewhat discretely.

The Weathermen disappeared for most of the '70s and '80s. Starting in the mid-1990s, former members began to emerge on the national and international scenes, finally feeling that they could be safe.