The Shelah's Prayer (Tefilat HaShlah), is a prayer for education of children. Many say this beautiful prayer on Erev Rosh Chodesh Sivan, as the Shelah wrote in the introduction to prayer.
In most calendar years, our policy is to have several weeks when we read a double parsha so that we are able to complete the Torah every year and make a Siyum HaTorah on Simchas Torah. Why and when does this happen?