I (will) have to get up early tomorrow


#1
  1. I have to get up early tomorrow.
  2. I will have to get up early tomorrow.
    Which of the above sentences is correct?

#2

They are both correct. To me there is a very subtle difference in meaning, but I can’t quite put my finger on it. One difference is that #1 is a stand-alone statement that could begin a conversation. It is something you have already planned - tomorrow I have to get up early:
“I have to get up early tomorrow.
Oh really, why?
I am going fishing and the best time is right before sunrise.”

The second would be used if you just now made the decision or something in the conversation makes you realize you will have to get up early:
“Hey, can you still take me to the airport tomorrow?
Sure, what time does your flight leave?
9AM, but they say I should be there two hours before.
I will have to get up early tomorrow.”