<Tr> <Th> MST </Th> <Td> 10: 15 pm on Dec 19, 2017 </Td> </Tr> <Tr> <Th_colspan="2"> Observance of DST </Th> </Tr> <Tr> <Td_colspan="2"> DST is observed in certain regions of this time zone between the 2nd Sunday in March and the 1st Sunday in November . </Td> </Tr> <Tr> <Th> DST ended </Th> <Td> Nov 5, 2017 </Td> </Tr>

Where does time zone change from mountain to pacific