not too bad

Girl: What time is it there?
Boy: It’s 9:40 p.m. How about there?
Girl:It’s 4.40 p.m.
Boy: oh, It’s about five hours difference.
Girl: That’s not too bad.
Could someone please tell me what " not too bad" here imply?

The speaker doesn’t consider it to be too great a time difference (for whatever she has in mind.)

Thanks, Mrs. Beeesneees. But I think " too bad" means " that’s a pity or that’s unfortunate etc". So how " not too bad" still has a meaning in the above conversation?

In the above conversation, ‘too bad’ is not a phrase meaning ‘That’s a pity’.

So, what is exactly meant by " bad" here? I mean by, “not bad”? I know the meaning of “too”.

It means not far from the best circumstance or outcome. For instance, consider the following conversation.

“Darn, I only scored a 92 on the test.”

“That’s not too bad, it’s still an A.”

“I know, but I really thought I would score 100.”

Thanks, Luschen. But does your explanation " not far from the best circumstance or outcome" have something to do with the conversation i gave?

Sure, the best circumstance would be to have it be the same time, so the five hours difference is better than a 10 or 12 hour difference.

I got it, now. Thank you so much, Mr. Luschen.