It can mean either - see you again/later in a few minutes or just a minute ago/a little while ago according to the context.
à tout à l'heure means 'see you later' in French. See you soon.'à tout à l'heure' means see you later (the same day)
'à tout à l'heure" means "see you later" (the same day)
"A tout à l'heure" means "see you later" in French. It means see you within the hour in French
The phrase 'tout a l'heure' means in a little while, shortly. In the word-by-word translation, the noun 'tout' means 'all, everything'. The preposition 'a' means 'to'. The definite article 'le'*...