I’ve seen this trick on Man vs. Wild, but I could never remember it. It’s a great tip for how to use a watch as a compass:
Hold a watch with 12 o’clock at your left then turn so that the hour hand points to the sun. The halfway point from the hour hand and the 12 is south.
However, be cautioned that this only works when:
1. The sun is visible and
2. It’s not a digital watch