All-time low in Florida, numbers receding (5)
I believe the answer is:
nadir
'all-time low' is the definition.
(I've seen this before)
'in florida numbers receding' is the wordplay.
'in' indicates a hidden word.
'receding' says the letters should be written backwards.
'ridan' can be found hidden inside 'florida numbers'.
'ridan' backwards is 'NADIR'.
(Other definitions for nadir that I've seen before include "least successful point" , "Floor of drain in need of repair" , "Very bottom, farthest from zenith" , "All-time low" , "Drain to lowest level" .)