What factor could cause a change in an established battle rhythm?

The factor that can cause a change in an established battle rhythm is higher headquarters' battle rhythm. This is because the operational tempo and scheduling of a unit are often aligned with directives and requirements set by higher command. If the higher headquarters adjusts its own battle rhythm—due to new operational priorities, changes in mission focus, or shifts in strategy—this can necessitate corresponding changes at lower echelons to maintain synchronization and effective coordination of efforts across the forces. The alignment ensures that all units are operating on the same timeline, enabling effective communication and logistics support, which are critical in a combined arms environment.

While unit morale, availability of resources, and weather conditions are important factors that can affect operations, they do not inherently require a change in the battle rhythm dictated by higher headquarters. Changes in these areas might lead to adjustments in tactics or strategy but do not directly influence the structural schedule of operations as dictated by command hierarchy.