Use of the will-future

When do we use the will-future?

The will-future is one future tense. There are other future tenses, e.g. going to-future, Present Progressive, Future Progressive/Continuous and Simple Present.

We use the will-future:

1. Future actions happen without the speaker's intention (birthday, weather, etc.)

The sun will shine tomorrow.
Peter will be 15 next Tuesday.

2. Predictions, assumptions (I think, I hope, I'm sure, I'm afraid)

I think Sue will arrive in Paris at 6 pm.

3. Spontaneous actions (not planned)

Hang on! I'll have a word with you.