[3] As an undergraduate, Mass performed research on Martian weather with astrophysicist Carl Sagan,[4] and on the role of sun spots and volcanic eruptions on historical climate conditions with climatologist Stephen Schneider.

[5] He received his PhD in Atmospheric Sciences from the University of Washington in 1978 with a dissertation on the role of African wave disturbances and climate variation in the Sahel region.

[7] Mass maintains a popular weblog in which he posts regular articles on meteorology, Pacific Northwest weather history, and the impacts of climate change[8] written for the general public.

[12] Mass has also expressed concern when media outlets and environmental organizations have made, in his opinion, exaggerated claims about the current impacts of climate change.

Starting around 2008, KUOW warned Mass to stop voicing his opinions about subjects such as math education on his weather segment on the show Weekday.

The show's host, Steve Scher, noted that holders of opposing viewpoints complained to the station that they deserved equal time.

[28] The next day, KNKX announced that it would stop airing Weather with Cliff Mass, effective immediately, citing "offensive and inaccurate" rhetoric in that personal blog post.

[29] Mass temporarily removed the words "Kristallnacht" and "Brownshirts" from his post, describing the passage that contained them as "a source of distraction to some", before restoring them.