Describes an action that will happen. In IELTS, it is often used for predictions or plans.
'Will + V' for predictions or spontaneous decisions. 'Be going to + V' for existing plans.
I think it rains tomorrow.
I think it WILL RAIN tomorrow.
In Writing Task 1, be careful to use the future tense if the year in the chart is in the future (e.g., 2050).