Hanuman vratham is observed on Margasira Shukla Trayodashi. During Hanuman vratham, Lord Ganapati is worshipped before proceeding for Hanuman puja.
In 2016, Hanumath Vratam date is December 12.
Here is the Hanuman vratam puja procedure:
In a sanctified puja mandapam, Lord Ganapati and Anjaneya idols are placed. The puja mandapam is decorated similarly to other pujas.
Lord Ganapati is worshipped initially to get rid of (vignas) obstacles. Lord Ganesh is worshipped with simple puja vidhanam. Then actual Hanuman puja starts.
Kalash or Kalasham, the clay-pot or bronze pot filled with water, be kept before the idol of Hanuman and a diya or deepam be lighted. Dhoop batti or incense sticks or Agarvatti should be lighted. After that Puja Sankalpam is recited.
Shodashopachar puja is offered (the main steps include – Shuddodaka snanam, panchamrita abhisekam, pushpabhishekam, naivedyam, and aarti). During the Hanuman vrat pooja, Hanuman Chalisa, Sankat mochan Hanuman stotram, Hanuman Asthakam, and some other Anjaneya stotras are recited. After the puja is over, Pradakshina (circumambulations) is offered to Hanuman and flowers and akshata (consecrated rice) are showered.