Based on the provided information, rainfall peaks between July and September, but without specific numerical rainfall amounts for each month, it's difficult to pinpoint a single "heaviest" month. We can, however, refine the answer based on the provided context:
- Rainfall peaks between July and September.
- There's a short dry break in August known as the 'August break'.
Therefore, the heaviest rainfall occurs in either July or September, with August experiencing a slight decrease in rainfall compared to these two months. The provided information indicates that the heaviest rainfall can likely be found in either July or September due to the "August break."
