Which factor is least likely to affect swing dynamics during a club fitting?

Temperature is least likely to affect swing dynamics during a club fitting for several reasons. When fitting a player for clubs, the primary focus is on physical attributes that directly influence the player's interaction with the club and their swing mechanics. These attributes include grip size, shaft flexibility, and club length, all of which have a direct impact on how a player can effectively swing the club and make contact with the ball.

Grip size plays a crucial role in how a player holds the club and influences their control over the club during the swing. Shaft flexibility affects the timing, loading, and unloading of the club, which can significantly alter swing dynamics and ball flight characteristics. Additionally, club length needs to be precisely matched to a player's height and swing characteristics to ensure optimal posture and swing mechanics.

While temperature can have some impact on the playing conditions and the physics of the game—for instance, how the ball travels in different weather—it does not directly influence an individual’s swing mechanics or dynamics in the same way that the physical attributes of the clubs do. Therefore, it is less relevant in the context of swing dynamics during club fitting.