The town of Strahan in Tasmania has a latitude of 42° S and longitude of 145° E. What will be the altitude and direction of the midday Sun there on March 21st?

The angle of the Sun below the vertical at noon is equal to the latitude, but only on March 21st and September 21st, the spring and autumn equinoxes - these are the days when there are exactly 12 hours of day and 12 hours of night.

Solar altitude refers to the angle of the sun relative to the Earth's horizon. Since the Earth gets 12 hours or light and 12 hours of darkness, and the sun climbs to an altitude equal to (90 - L) degrees above the horizon.

Then, this is (90 - 42) = 48° about the horizon, which is just over halfway to the zenith.