A variable checkpoint mechanism in a streams manager checkpoints a streaming application based on periodic time periods for checkpoints. The variable checkpoint mechanism can take a checkpoint before a periodic time period ends when a spike is coming, or can take a checkpoint after the periodic time period ends when there is backpressure in a consistent region of the streaming application. When there is no anticipated spike coming and when there is no backpressure in a consistent region of the streaming application, the checkpoint is performed at the normal end of the periodic time period for checkpoints. In this manner the checkpoint timing of the variable checkpoint mechanism can be adjusted real-time to minimize the negative impact of checkpointing on the performance of the streaming application.