If you work in a U. S. national lab everything is done in metric. It was something I got used to using. I usually didn't have to convert anything as work was simply done in metric from the beginning. All research publications used metric. So in an official sense, the U. S. uses metric.
I do remember that 40 C was about 104 F though (I was curious and looked it up because it was temperature of a water bath).
