Today, was.
Or rather, "is".
But during Tomorrow, it will be "was".
Unless Tomorrow is Yesterday, then it would be "will be".

But if Tomorrow was Yesterday, then we would be living in two days:
One for Today,
And one for Today/Yesterday.

But if that were true, then life would be paradox;
And we would be fated to think about this again. (In two day's time)