I tried figuring out where to post this and took a chance on this forum.
Seems like the DST setting for Brazil is wrong. My clock is on DST already, but the change is not until next week-end. I am not sure if there really is a system to how Brazil do this. I noticed that Windows clock is also off. I am not sure if Brazil have an exact system for this change, maybe you just have to enter the dates in a table for the next few years and keep updating this setting as things change...
EDIT - After checking with my Brazilian wife and doing a little more research, this came from WikiPedia:
Brazil adopted DST (called horário de verão – "summer time" – in Portuguese) for the first time in 1931, and has used it continuously since 1985 in the southern states (south, southeast regions and the states of Goiás and Mato Grosso do Sul), and in Bahia until 2004. Formerly, starting and ending dates were variable, but in 2008, a decree established a permanent rule: DST starts at 00:00h on the third Sunday in October and ends at 00:00h on the third Sunday in February -- except if it falls during Carnival; in this case, DST ending is postponed one week. The next year in which DST ending will be postponed is 2012. In 2008, DST starts on October 19, 2008 and ends on February 15, 2009 in the states of Rio Grande do Sul, Santa Catarina, Paraná, São Paulo, Rio de Janeiro, Espirito Santo, Minas Gerais, Goiás, Mato Grosso, Mato Grosso do Sul, and Distrito Federal.
So Brazil USED to have a variable DST setting. But now they switched to a predictable system. Well, I guess that is a good time
This should probably get into some kind of fix or update for Mint.