Regular dates arranged at the end of January (6)
I believe the answer is:
steady
'regular' is the definition.
('steady' can be a synonym of 'regular')
'dates arranged at the end of january' is the wordplay.
'arranged' is an anagram indicator.
'at the end of' indicates one should take the final letters.
The last letter of 'january' is 'y'.
'dates' with letters rearranged gives 'stead'.
'stead'+'y'='STEADY'
(Other definitions for steady that I've seen before include "Not shaking or moving" , "Not wobbly" , "Get a grip!" , "Maybe 'staid'" , "Well secured" .)