The longest lasting tropical cyclone lasted 31 days, it was named Hurricane/Typhoon John and travelled through the eastern Pacific Ocean from 11 August - 11 September 1994.
Hurricane/Typhoon John formed on 11 August 1994 in the eastern Pacific Ocean. It lasted for 31 days and also travelled the furthest distance recorded for a tropical cyclone: 13,280 km. As it travelled from the eastern to the western Pacific, it became one of only a handful of tropical cyclones to be labelled as both a hurricane and a tyhoon.
Comments below may relate to previous holders of this record.