Derbyshire 17 for 0 trail Glamorgan 259 (Carlson 94, Reece 4-67, Dal 3-29) by 242 runs
Glamorgan are on the brink of celebrating a return to the top tier of domestic cricket for the first time in 20 years after the Rothesay County Championship Division Two match against Derbyshire at Derby ended in a draw.
For the second day running, rain prevented any play at the Central Co-op County Ground which means third place Derbyshire cannot now overtake the Welsh County in second place
Barring an extraordinary ending to Middlesex's match against Lancashire at Old Trafford, Glamorgan will be playing Division One cricket next season for the first time since 2005.
They went into the last day already in a strong position but once rain throughout the morning washed out the first session, it was obvious Derbyshire's slim hopes had gone.
The decision to abandon the match was taken after a brief inspection by the umpires and both captains shortly before 12.30pm with Derbyshire taking 11 points and Glamorgan nine points from a game in which play was only possible on day two.
Glamorgan end the season with a home game against Lancashire while Derbyshire travel to Canterbury to play Kent.