It's cold definitely, but it's not too bad. Wear the appropriate clothes, light the fire or run your heater and it's all good! One good thing is you do get to appreciate the seasons and when Spring comes you really do notice it.
I hate Toowoomba winter, it's bitterly cold and then you get torrential downpours, so you end up wet and cold all the time. And the really thick fog settles in for days on end, and you cant see anything, which makes driving a nightmare. It doesnt matter how many layers you wear, the wind just cuts straight through. The good thing about winter however is that it is generally short, however never short enough.
Toowoomba has a very mild winter by international standards. Snow is extremely rare, the warm sun shines most of the time, and it remains dry. We have friends who live in Los Angeles, which has the best climate in the world and they say that our climate in Toowoomba reminds them of home! Great opportunity to dress up - wear a coat or jacket when you go out, and be sure to buy some flannelette sheets for the bed.
The Toowoomba winters are comparable to those of Tasmania. I whethered eleven of those and, even though I was a teen back then, it stiffened up my joints. Toowoomba did the same for me. However, Toowoomba doesn't have those Antarctic catabatic winds one can get during a Tasmanian winter. They cut through a person worse than those westerlies.