Rainmachine Pro 16, Ethernet connected.

I don't understand how connecting my RM to the weather on the internet (Australian Weather) works and whether it's worth it.   Here in Melbourne we've had heavy rainfalls over many days/weeks.   The worst of the weather stopped about a 7 - 10 days ago.   During this period the RM programs didn't water, correctly so.   It hasn't rained for the last 3 days and on every day my RM programs haven't watered and the notification is that there is a surplus of water.   Yesterday and today, I manually ran the programs.  

Checking the weather forecast that RM receives seems to be in sync with the weather forecasts that I check elsewhere, and therefore accurate.   Why after 3 days does RM not want to water?

Any help appreciated?

Steven