Will and Going to
If we are not so certain about the future, we use 'will' with expressions such as 'probably', 'possibly', 'I think', 'I hope'.
- I hope you'll visit me in my home one day.
- She'll probably be a great success.
- I'll possibly come but I may not get back in time.
- I think we'll get on well.
If you are making a future prediction based on evidence in the present situation, use 'going to'.
- Not a cloud in the sky. It's going to be another warm day.
- Look at the queue. We're not going to get in for hours.
- The traffic is terrible. We're going to miss our flight.
- Be careful! You're going to spill your coffee.