I think these are so nifty, but I live in Southern California, and we've had this drought of historical proportions for the last few years. I do own a couple of winter coats (one parka, one wool), and it occurred to me last winter that unless we go visit my sister in Oregon, I just haven't used them in years. Throwing on a sweater is all you need when it's this temperate all the time. Winter 2015-16 was supposed to be the big El Niño with all the rainfall, so I was pretty excited, and then it didn't happen. (There's a meme about the top 5 things people in SoCal get excited about: one is avocados, another is In 'n' Out Burger, and then the other three are rain. And it's true.).
Anyway, I gave up on the idea of doing a temperature scarf if even El Niño couldn't give us some real weather. And then winter 2016-17 hit, and we've actually had lots of colder days and plenty of rain. It's been lovely-- the hills are green again for the first time in years, and there's snow on the mountains-- but I wasn't expecting it, so the temperature scarf thing didn't occur to me. I'm feeling like an idiot for missing the opportunity. Gah. Well, I have four kids and a husband who are as nerdy as I am and who all want stuff like Harry Potter Weasley sweaters, so I have plenty to keep me busy.