Pilgrimage to Sabarimalai will start from 1st of Vrichikam, a Malayalam month coming in the middle of November (probably between 14-16). The most important day for Ayyappan is on Makarasamkranthi day, that is the 1st of Makara month of Malayalam Caledar. This day will fall between January 14-16. Currently millions of devotess coming from all parts of India to Sabarimala for a glimpse of Lord Ayyappa.
See this external link for more information about Sabarimala and Lord Ayyappa. " class="external">http://www.ayyappa.com/Sabarimala.htm