You can catch one at the junction when the weather's wet (5)
I believe the answer is:
train
'you can catch one at' is the definition.
I can't tell whether this definition defines the answer.
'junction when the weather's wet' is the wordplay.
I cannot quite see how this works, but
'junction' could be 't' and 't' is found in the answer.
'wet' could be 'rain' (wet weather) and 'rain' is located in the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
'the' acts as a link.
Can you help me to learn more?
(Other definitions for train that I've seen before include "Coach, develop" , "Suite; give practice (in)" , "Trailing part of bridal dress" , "Railway engine" , "Public transport on the railway" .)