Double it and add 30 for a rough estimate. Gets less accurate as the temps rise.
We Canadians know both, thanks to Prime minister Trudeau.
Americans are the last place still hanging on to imperial.
Even your doctors use metric.
Values of ten, just makes sense.
Zero is freezing and 100 is boiling.
Silly americans .......
There is a sizable population in the US that would think going on the metric system would be Socialism. I'm not sure whether they are fools or just racist.