nhtempCelsius <- 5*(nhtemp - 32)/9

plot(nhtempCelsius, axes=FALSE, ann=FALSE, ylim=c(0, 13))

axis(2, at=seq(0, 12, 4))
mtext("Degrees Centigrade", side=2, line=3)

axis(1)
axis(4, at=seq(0, 12, 4), labels=seq(0, 12, 4)*9/5 + 32)
mtext(" Degrees Fahrenheit", side=4, line=3)
box()