However, it's important to note that:

* The transition wasn't immediate: The BOM started using Celsius in its official forecasts in 1974, but some regional areas continued to use Fahrenheit for a few years after that.

* Fahrenheit still persists in some contexts: You might still see Fahrenheit used in some older weather records, or in specific contexts like aviation or engineering.

So, while 1974 is the official date of the switch, it took a while for Celsius to become universally adopted in Australia.