It's Saturday. / Today is Saturday.

[xiaoen]

1. It's Saturday.
2. Today is Saturday.

Hi,
Can we say that the above blue sentences have the same meaning?
I wonder how #1 means today. I'm not really sure about their difference.

For example if you ask me "What day is today?"
Can I answer "it's Saturday."? Or I should say "Today is Saturday"?

 

[emsr2d2]

"It's Saturday" is also a natural answer to the question "When's your birthday?" or "When's the party?" if the event is going to take place on the first Saturday after the words are spoken. It would be more natural as "[It's] on Saturday" in BrE but you'll hear it without the preposition.

 

[Tdol]

What day is it today? is a more natural question to me.

 

[xiaoen]

1. What day is it today? (correct)
2. What day is today? (correct)
3. What day is it?

Hi,
I know that #1 and #2 are correct but what's your opinion about #3? Do the above three questions have the same meaning?