I grew up in Canada, but in a temperate climate area on the border with the US. Winter? Use Celsius. Summer? Use Fahrenheit. For me Celsius makes a lot more sense right around 0C. After about 15C my brain switches over and starts using Fahrenheit. I like the Fahrenheit scale from 60-100F for gauging the summer months. The Celsius scale isn’t granular enough. It feels like there’s a big difference between 18C and 22C versus the comparable 64F-72F. But I also was taught early a quick and dirty conversion. C to F, double and add 30. F to C subtract 30 and divide by 2.