Refinement to sun/wristwatch estimate of N/S direction
The method is generally reliable between 9 am and 3 pm.
The other consideration is when one is using the method in either of the tropics: Cancer or Capricorn.
It is generally accepted that in the northern hemisphere, the sun is located in the southern part of the sky and the opposite in the southern hemisphere. This applies to latitudes greater than the latitudes of the Tropics. Between the equator and the Tropics, depending on the time of year, the position of the sun in the sky alternates between north and south.