The Second Pinnacle is the one most clients are living in when they have a chart read, since it typically runs through the thirties and into the forties. That position in the sequence gives it a job the others do not have.
A reading of a past pinnacle is an interpretation. A reading of a future one is a forecast. A reading of the present one is advice, and it is the part of the consultation where a practitioner is actually being asked what to do. The literature reflects that: the descriptions of the second pinnacle are written in the imperative far more often than the descriptions of the first, and they concern work, partnership and the decisions that are reversible only at cost.
The figure is the reduced birth day added to the reduced birth year, reduced again, which makes it the only pinnacle combining the most individual input in the chart with the least individual one. Everyone born in the same year contributes the same second term.
That has a visible consequence. Within a birth cohort, the Second Pinnacle varies only with the day of the month, so it takes a limited set of values across everyone born that year, and people of the same age are frequently told they are in the same phase. Practitioners who read for groups notice this and generally treat it as a feature, since a cohort sharing a phase is what a generational reading would predict anyway.