Dreams cannot predict the future.
Likely you are referring to Deja reve ('already dreamed'), which has been hypothesized to be (Schredi et al., 2017):
...the distinct impression that the uncanny familiarity one is
sensing has come from a preceding dream, but one not usually
remembered until the experience is taking place.
Deja reve are reported by Schredi et al. to occur in nearly 80% of the population.
Dreams are representations of past experiences (re-)generated is our minds creates while we sleep. It has been proposed that dreams reflect biological processes of long-term memory consolidation. Consolidation strengthens the neural representations of recent events (i.e., their memories) and embeds these new memory fragments into older, existing memories. This also maintains the stability of existing memory representations in the face of subsequent experiences (Payne & Nadel, 2004). In sleeping rodents, for example, neurons in the hippocampus fire in patterns remarkably similar to those recorded during a previous maze-running session—almost as if the animals replay the experience in their sleep (source: Science Magazine).
In all, dreams are related to memories and memory formation. However, they have nothing to do with future events. The brain cannot recall what never has perceived in the past. Hence, déjà vu experiences and dreams have nothing to do with what the future may bring, other than cases of pure coincidence.
- Payne & Nadel, Learn Mem (2004); 11(6): 671–8
- Shredi et al., J Consciousness Studies (2017); 24:(7-8): 155-62