Shiva (Rudra) is the destroyer of ignorance and as such is considered to be quite “hot”. So in most temples there is a schedule of rudra abishekams that take place as often as every two to four hours throughout the day.
In the photo below the Shiva lingam is seen in the center with the priests surrounding it, having completed the abishekam process. The lingam has been “dressed” in a fresh dhoti and decorated with vibhuti (sacred ash).
During Rudra Abishekam, two hymns from Yajur Veda are chanted; Rudram which honors Shiva in his many forms, and Chamakam which asks him for all sorts of blessings.