Precipitation ultimately unknown in Tamworth, perhaps? (4)
I believe the answer is:
snow
'precipitation' is the definition.
(I know that Snow is a type of precipitation)
'ultimately unknown in tamworth perhaps?' is the wordplay.
'ultimately' says to take the final letters.
'in' means one lot of letters goes inside another.
'tamworth perhaps?' becomes 'sow' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
The final letter of 'unknown' is 'n'.
'n' placed into 'sow' is 'SNOW'.
Can you help me to learn more?
(Other definitions for snow that I've seen before include "feature of 27 [THE BIG FREEZE]" , "Wintry precipitation" , "Weather feature" , "TV newsman" , "Cold precipitation" .)