There are three time zones in Chile: continental Chile, Easter Island and Magallanes Region. Clocks change only in two time zones: continental Chile (the offset or time difference goes from GMT-3 to GMT-4) and on Easter Island and Salas y Gomez Island (from GMT-5 to GMT-6).
In 2019, Continental Chile goes to Daylight Saving Time at midnight on 8 September. Clocks will return to Standard Time on 4 April 2020. Easter Island moves to DST two hours before Continental Chile, at 2200 hrs on 7 September 2019. Magallanes Region does not operate DST.
Chile reintroduced Daylight Saving Time in 2016.
The move back to DST was announced in May 2016, when the government decided that Standard Time would revert to GMT-4, and Daylight Saving Time would start on 14 August 2016.
One year earlier, in 2015, the government had introduced a permanent DST offset, which meant GMT-3 throughout the year on continental Chile and GMT-5 on Easter Island.
Previously, the DST rule in Chile was from mid-October (First Sunday on or after 9 October) until mid-March (First Sunday on or after 9 March).
Read more about the history of clock changes in Chile in this Wikipedia article.