Tomorrow is predicted to be 46 C, which I think would equal the all-time record for where I am. There's also a large coast/inland variance, so forecasts for 'Sydney' (usually taken at Observatory Hill, one of the coolest places in the city) are significantly lower. I am only about 25km from the city centre, but it will only get to 35 C. There is typically a 5 C difference in summer, but 10+ C is fairly unusual.
I recall two previous days around this temperature. One was two years ago on a day I decided to go to the cricket. It was about 44 C at the ground, and the lack of a heat differential between the city and suburbs was unusual. It was pretty unbearable to sit in, just watching. Tomorrow it will likely only be about 36 C at the cricket.
The other day I recall had a reasonable differential between city and suburbs, but I'd unfortunately pre-planned to go to pretty much the hottest place in Sydney. It got up to about 47 C.
The worst thing about tomorrow's temperature may be how long it lasts. Often an afternoon change will come and blow the hot air away. Tomorrow it's currently predicted to still be 45 C at 5pm, and 37 C at 8pm.