If you want to talk about things taht are most certainly going to happen in the future, you can use the Present Continuous. You've already made arrangements to make sure the event will take place:
We are having a party next week, here's an invitation.
I am going to spain next summer, I'm so excited!
He is working abroad next week, so if you want to talk to him; do it now.
You may also use the present continous is you're predicting something following earlier clues:
Look at that blue skye! It'sgoing to be a lovely day.
We aren't going to see any leopards here, they're moved to another zoo.