Farewell to cold winters, and hello endless summer in Sydney

I was preparing some materials for this intro to python workshop and wanted to have some interesting data. We're having a heatwave in Sydney at the moment, where the temperatures at night are still stiflingly hot and sleeping is difficult. So I thought something about hot nights and memories of cold days might be nice.

Sydney "feels like" winter when the maximum temperature is below 20. It means you have the heater on (or it means I need to light a fire). It feels like summer when the minimum temperature is above 20;  you have to sleep with at least a fan but you can dive into the pool or sea any time of the day or night and it isn't uncomfortable.

Here's how many winter-like days there were vs the number of summer-like days.



So is Sydney becoming the city of endless Summer? Who wants to take a bet on the first year when there are more summer-like days than winter-like days? I'm guessing around 2020.

I've saved the Jupyter notepad (including where to get the source data) here:
https://github.com/solresol/python-workshop/blob/master/curriculum/02-materials/code/farewell-winter-endless-summer.ipynb -- feel free to modify it and/or try it out for data in your city.