It depends on a number of factors, not just the season. In the spring and in summer the process is accelerated by the increased outdoor temperature. If you start to compost in the spring, you will need about 3 months. In autumn and winter the process slows down because due to the low temperatures most of the organisms reduce their activity. If you start in the fall, the process will really start in the spring and you will need 9 months to get compost. It is important to noted that the composter can continue to be used during the period of “low activity “as you stockpile it with biodegradable materials for the time you microbial activity increased. In a well-aerated container in which there is a balance between “brown” and “green”, the humidity is optimal and the waste is cut into smaller pieces, the materials will decompose much faster than when one of these factors is neglected.