The farthest has been 17 minutes , from 1991 to 1995 , after the signing of the Strategic Arms Reduction Treaty . Clock is now set at six minutes to midnight , Chicago - based group says . Midnight represents a nuclear apocalypse . Doomsday clock had been adjusted only three times before Thursday . It was five days after the signing of the Strategic Arms Reduction Treaty .
Clock is now set at six minutes to midnight , Chicago - based group says . Midnight represents a nuclear apocalypse . Doomsday clock had been adjusted only three times before Thursday . It was five days after the signing of the Strategic Arms Reduction Treaty .