Weather table these are feature of periodically? (8)
I believe the answer is:
elements
'weather table' is the definition.
'elements' can be an answer for 'weather' (I've seen this in another clue). I'm not sure about the 'table' bit.
'these are feature of periodically?' is the wordplay.
'these are feature' becomes 'element' (I've seen this in another clue).
'of periodically?' becomes 's' (I can't justify this - if you can you should believe this answer much more).
'element'+'s'='ELEMENTS'
Can you help me to learn more?
(Other definitions for elements that I've seen before include "Carbon, iron and 8 Across, say" , "Fire, air, earth, water" , "Essential parts or the weather" , "Components or weather conditions" , "live wires?" .)