How Does Time to Expiration Influence the Delta of an ITM Option?

As time to expiration decreases, the Delta of an In-the-Money (ITM) option moves closer to 1 (for calls) or -1 (for puts). With less time remaining, the probability of the underlying asset's price reversing and making the option expire Out-of-the-Money diminishes significantly.

This increased certainty that the option will be exercised causes it to behave more like a forward contract or the underlying asset itself. Conversely, with a long time to expiration, the Delta is slightly lower than 1 due to the possibility of a large adverse price movement.