According to many news sources, 32 municipalities in Mato Grosso will change their clocks for DST the coming weekend, so this will split Mato Grosso into two different zones. One example: http://www.redenergia.com/concessionarias/noticias/5476/Concessionarias-Gera... Biggest city we could find among them was Barra do Garças. Our view of it: http://www.timeanddate.com/news/time/brazil-time-changes-2011.html Best regards, Steffen Thorsen - timeanddate.com