What is the playing conditions calculation (PCC)?

The PCC is an automatic daily check of whether the course played harder or easier than normal because of weather, course conditions or set-up. It compares the scores submitted that day with expected scoring patterns.

• It can produce an adjustment of −1.0, 0, +1.0, +2.0 or +3.0, applied to everyone's Score Differential for that day on that course. A +2.0 means conditions were judged harder, so your differential is reduced by 2.0.
• It needs at least 8 acceptable scores from players with a Handicap Index of 36.0 or lower; with fewer, the PCC is 0.
• It is normally calculated once a day, though more than one can be run if, for example, the weather changes sharply between two parts of the day.
• Scores submitted after the day of play aren't included in the calculation, but the day's PCC is still applied to them.

That's why you should submit your score before midnight on the day you play.

Source: Rules of Handicapping (2024), Rules 4.3 and 5.6.