Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Indianapolis to Brasilia as you normally would.
In terms of precipitation, rainfall in Brasilia ranges from 0.0 - 13.0 inches per month. December is typically the wettest month, when rainfall can reach 13.0 in. June is typically the driest time to visit Brasilia when rainfall is around 0.0 in.
If weather is an important factor for your trip to Brasilia, use this chart to help with planning. For those seeking warmer temperatures, September is the ideal time of year to visit, when temperatures reach an average of 75.2 F. Travelers looking to avoid the cold should look outside of June, when temperatures are typically at their lowest (around 68.0 F).