What is the standard number for west variation?

The standard number for west variation, often referred to as magnetic declination, is indeed approximately 15 degrees. This angle indicates the deviation of magnetic north from true north in a westerly direction. Understanding this concept is crucial for navigation, as it allows mariners to adjust their compasses accordingly to ensure accurate course plotting.

When navigating, it’s essential to know the magnetic variation for the area you are operating in, as it can change based on geographic location and fluctuate over time. The values commonly encountered in navigational contexts can vary, with 15 degrees serving as a commonly referenced figure in certain regions. This does not mean that other values like 10, 20, or 25 degrees are without merit; they may represent the magnetic variation in different geographic locales or under different conditions.

Therefore, recognizing that 15 degrees is an accepted standard for west variation aids in understanding and improving navigational accuracy, making it a vital part of navigation training.