Tot comes with me to river when it's hot? (6)
I believe the answer is:
summer
'it's hot?' is the definition.
(I know that summers are often hot)
'tot comes with me to river' is the wordplay.
'tot' becomes 'sum' (synonyms).
'comes with' is a charade indicator (letters next to each other).
'to river' becomes 'r' (abbreviation for river).
'sum'+'me'+'r'='SUMMER'
'when' acts as a link.
(Other definitions for summer that I've seen before include "'. . . . . . time an' the livin' is easy' (song)" , "year" , "'Shall I compare thee to a . . . . . .'s day?' (Shakespeare)" , "warm spell" , "Best of times" .)