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Buys Ballot’s Law

In the realm of meteorology, there are few laws as elegant, simple, and valuable as Buys Ballot’s Law. Named after Dutch meteorologist C. H. D. Buys Ballot, who first formulated it in 1857, the law provides a relatively easy way to determine wind direction and, consequently, locate areas of high and low pressure. Understanding Buys Ballot’s Law can offer clues to location and directional orientation for sailors, hikers, and even lost adventurers.

What is Buys Ballot’s Law?

Buys Ballot’s Law states that when standing with your back to the wind in the Northern Hemisphere, low pressure will be to your left and high pressure to your right. In the Southern Hemisphere, the opposite holds: with your back to the wind, low pressure will be on your right and high pressure on your left. This is due to the Earth’s rotation, specifically the Coriolis effect, which influences how air moves around pressure systems.

Practical Application for Determining Location and Direction

At Sea

Sailors have used this rule to ascertain their relative position to weather systems. If they are sailing in conditions where the wind is coming from the west, and they note that the weather is deteriorating on their left, they can deduce that they are approaching a low-pressure system. This helps sailors make a more informed decision on whether to change their course to avoid bad weather or prepare for upcoming storms.

In the Wilderness

Hikers can also benefit from Buys Ballot’s Law. Feeling the wind and understanding its implications can give you critical information if you are in an area without a compass. For example, knowing the general flow of air masses in your region can help you decide which direction to move in to find shelter or more favorable conditions.

In Aviation

Pilots use a more technical version of Buys Ballot’s law combined with their meteorological data to make decisions during flights. Knowing where the high and low-pressure systems are can be a matter of safety, especially during long flights over large bodies of water or uninhabited land.


While Buys Ballot’s Law is applicable, it is not infallible. It works best when you’re far from the center of a low-pressure system, as wind direction can be more unpredictable closer to the center. Also, local geographical features like mountains can distort wind patterns, making the law less reliable. Moreover, it’s vital to understand that the law gives a general guideline, not an exact reading of pressure systems or your specific geographic location.

Buys Ballot’s Law offers a convenient way to understand your general orientation relative to large weather systems and, by extension, your location and direction. While not a replacement for modern navigation tools and meteorological data, it can be a valuable asset when such tools are unavailable or you need to make quick decisions based on environmental conditions.

So, the next time you find yourself outdoors, pay attention to the wind and its clues. You may find that nature is one of the best navigational tools at your disposal.

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