I've been searching the internet for some time now, and I just can't find an explanation.
Many adverbs are marks as 'termporal noun' on jisho.org, but I wonder what that means... I can guess what they are, but I'm a bit confused about their use. Are they nouns? Are they adverbs?
I may be completely wrong but it looks like what you are referring to are nouns that are times. "Temporal" just means relating to time. So, for example there's 1時 - 1 o'clock or 昨日 - yesterday. They are nouns, function as nouns, but they're just times.