My Galaxy Nexus, Jelly Bean, was set to Automatic Date & Time, Automatic Time Zone, and the correct Time Zone was shown: "GMT -03:00, Brasilia Time". Here in Brazil Daylight Saving Time begins today. Android didn't detect that.
To be fair Microsoft for many years also made the DST start in the wrong week in its Windows products. If I recall correctly, it required a new law from our Government to make the DST more predictable, so in the last few years Windows got it right.
I don't know if Android will make the DST start in the wrong weekend or if it won't work at all. How can I correct it?