Is the monsoon season in Asia considered a "Known Event"?

The monsoon season is a seasonal occurrence and would only be considered a "Known event" if it is deemed significantly serious enough to potentially affect your travel plans. 

So unless a specific severe weather event or a natural disaster has occurred prior to the purchase of your policy, you would still have cover to travel to Asia during the monsoon season.
Our Comprehensive, Standard Saver, Snow Sports Plus and Frequent Traveller Saver policies provide Cancellation cover in case of unexpected events which directly impact your travel plans and cause you to cancel your trip. These unexpected events include severe weather or a natural disaster. However, you would only have cover if you purchase your policy BEFORE the severe weather or natural disaster occurs, or before it becomes a known event.
When looking to purchase your travel insurance policy, you should check for events that have already occurred at your travel destination/s as these events may impact your cover and what you can claim for. The best way to identify a known event is to check:

Cover is subject to the policy terms, conditions, limits and exclusions in the Product Disclosure Statement (PDS).