Why is weather forecast for Sydney so completely wrong?

I recently moved back to Sydney. The built-in weather app on the FR970 (updated to 15.16, but issue was same before) is that the weather forecasts for the coming days is *completely* wrong. The local BoM (Bureau of Meteorology) and weather.com and accuweather all show roughly the same, the Garmin app shows almost European weather. I have checked and even manually added the location and it's the same.

Where does Garmin source it's weather data and is there any other setting that could be part of this?