How Does a “Zero-Day-to-Expiration” (0DTE) Option’s Delta Behave Compared to a Long-Dated Option?

A 0DTE option's Delta is highly unstable and moves much more rapidly than a long-dated option's Delta. Near the strike, a 0DTE option's Delta will move sharply from near 0 to near 1.0 (or -1.0) with a tiny move in the underlying asset's price, due to its extremely high Gamma.

A long-dated option's Delta changes more gradually, as it has more time value and lower Gamma.