Overly dim tallyman arrived in January (9)
I believe the answer is:
midsummer
'january' is the definition.
The definition and answer can be both related to time as well as being singular nouns.
Perhaps you can see an association between them that I don't see?
'overly dim tallyman arrived' is the wordplay.
I cannot quite understand how this works, but
an anagram of 'dim' is 'mid' which is located in the answer.
The remaining letters 'summer' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
'in' is the link.
Can you help me to learn more?
(Other definitions for midsummer that I've seen before include "Play with fairies and 'mechanicals'" , "Fantasy in late June" , "June twenty first" , "Solstice time" , "Warm spell" .)