Techniques for determining a hydraulic fracture dimension include identifying pressure signal values of a first fracturing fluid in a monitor wellbore that represent a pressure change in the first fracturing fluid that is induced by formation of a second hydraulic fracture from a treatment wellbore; determining a particular pressure signal value of the plurality of pressure signal values; based on the determined particular pressure signal value, determining a particular dimension of the second hydraulic fracture formed from the treatment wellbore; and determining, based at least in part on (i) the determined particular dimension, and (ii) a first pressure signal value of the plurality of pressure signal values that is less than the determined particular pressure signal value, a first intermediate dimension of the second hydraulic fracture that is less than the determined particular dimension of the second hydraulic fracture.