If you are going to visit Burj Khalifa in Dubai, I suggest you buy tickets for the afternoon. You will have plenty of things to do in the tower until the evening. The Burj Khalifa is currently the tallest building in the world. You can see the birds that fly through the skies of Dubai from here. If you want to learn about the story of the construction of Burj Khalifa, you will have to go to the lobby. After going up to the top, there are still a few floors to visit. There is a semi-open floor and two large glass floors to watch the sunset. In the middle, there is a place where you can purchase souvenirs from. You can also choose to sit in front of the glass windows and wait for the sunset quietly. After the sun sets, you can watch the fountain show in the square below on the other side. So, this time period is the most appropriate.