In the winter, why can a period of time be sort of warm, but it can become extremely cold just a few days later?

https://www.quora.com/In-the-winter-why-can-a-period-of-time-be-sort-of-warm-but-it-can-become-extremely-cold-just-a-few-days-later

My reply:

Because all weather is driven by the Sun, and its ever-changing distance and angle along with varying sunspot activity create not only weather but the seasons, which despite some flukes is still in a wonderful balance. But the Earth has a surface area of 197 million sq. mi., so ‘’it’’ happens somewhere all the time.
The big debate now is about climate, a long-term average. Yet extreme weather not only can affect the average, it might be a signal of a permanent change, adding spice to the debate. I for one know that CO2 has been framed as a climate control knob, and we must look elsewhere, but one thing for sure, without the wonderful fossil fuel industry we’d all be heating our homes with logs or dried manure and riding horses in the mud. The fossil fuel industry too has been framed, with CO2 being a convenient excuse after they cleaned up their smokestacks of CO, SO2, soot, etc. Actually, the fossil fuel industry is indispensable, and the only reasonable alternative is nuclear not iffy wind and solar energy.
Elizabeth Warren’s Wonderful New Green World
https://principia-scientific.org/computer-model-delusions-and-the-climate-scare/
http://www.climatedepot.com/2019/01/29/record-cold-snow-caused-by-global-warming-climate-activists-predict-both-outcomes-more-snow-less-snow-so-they-are-never-wrong-book-excerpt/