Depends entirely on context, though grammatically it's most likely to be habitual.
Cannot be a singular action-- would be "If he gets home on time, *we'll* go out for dinner". But I would prefer it to be "*an* habitual action"!
I'm terrible at this type, but I went with my gut and said habitual.
I can use this as a single action if I'm giving a series of options:
A: Where are we eating dinner tonight?
B: Well, if it's warm and sunny we eat on the patio. If it's cold we eat inside.
To my ear it sounds like someone older is giving me instructions on what to do.