Going back to the OP
It states
"Sydney will experience 11 days above 35C by 2090, an increase from three days in 1995."
What part of Sydney ? See below
SYDNEY CBD, an average of 14.9 days a year have temperatures of more than 30 °C (86 °F)
and 3.0 days with temperatures over 35 °C (95 °F)
In contrast, western suburbs such as Liverpool and Penrith have 41.4 and 67.5 days of temperatures above 30 °C (86 °F),
10.2 and 19.0 days above 35 °C (95 °F),"
So 50kms, the number jumps.
You only have to knock off the sea breeze on a couple of days and it will jump in number.
It's like where I live, just out of Melbourne but in a rain shadow, compared to the east of Melbourne that gets dumped on.
