No doubt, some watches are packed with complications that do all kinds of unique things. One simple trick works with any analog watch, though: using it as a compass. With the sun, a watch, and a little know-how, you can find the cardinal directions (north, south, east, and west).
So, how do you use a watch as a compass? Well, it depends on which hemisphere you’re in and how far from the equator you are. Keep reading to learn more about this helpful trick taught to Army Rangers for navigating without a compass.
How to Use a Watch as A Compass in the Northern Hemisphere
If you are in the Northern Hemisphere (most of you probably are), you’ll follow these steps to orient yourself.
First, take your watch off and hold it in the palm of your hand with the dial facing up. Make sure that the watch’s case is parallel to the ground.
Turn yourself or rotate the watch so that the hour hand is pointing towards the sun’s position in the sky.
If it is morning, look at the angle between the hour hand and the 12 o’clock mark on the watch’s dial, measuring clockwise. Bisect this angle by taking the middle point between the hour hand and the 12 o’clock mark.
If it’s afternoon, bisect the angle, measured counterclockwise between the hour hand and 12 o’clock on the dial.
If you’re in daylight savings (between March and November in most of the U.S.), you’ll have to adjust this method. Instead of using the 12 o’clock mark, you’ll use 1 o’clock.
This middle point between the hour hand and the hour mark will be pointing south. Now you can imagine a straight line running between this point in the middle of the watch’s dial to the other side of the dial. This point will be north. Using this imaginary north/south line, you can now determine east and west as well.
How to Use a Watch as A Compass in the Southern Hemisphere
Things change a bit if you’re in the Southern Hemisphere. Again, you hold the watch in your hand with the dial facing up and the case parallel with the ground.
In the Southern Hemisphere, though, you’ll rotate yourself or the watch so that the 12 o’clock mark is facing the sun’s position in the sky.
Then you’ll bisect the angle between the hour hand and the 12 o’clock mark to find the middle point. In this case, that point will be facing north, rather than south. Then you can draw an imaginary line through the middle of the dial to the other side to find south.
You might have to adjust for daylight savings time, too. In this case, you’ll point the 1 o’clock mark towards the sun.
Essential Things to Keep in Mind
There are some things to keep in mind when using this method. First, don’t use this method to replace a compass. You shouldn’t rely on this as your primary navigation method.
This is because of my second point: this is not as accurate as using a compass. In fact, in some cases, it isn’t going to be accurate at all. The closer you are to the equator, the less precise it gets. So, if you’re in the tropics, forget this method.
Finally, the shape of time zones affects accuracy. In the U.S., the time zones are wide and vary in size. People on the eastern and western sides of a timezone will have the same time set on their watches, but the sun’s position in the sky will be slightly different.
Using a Compass Watch Bezel
You may have seen watches with the cardinal directions marked in their bezels. These watches are designed to be used with the method I described in this post.
Sometimes the bezels are exterior and look like a dive bezel. These are different from the bezels found on dive watches, though. You can turn these compass bezels both clockwise and counterclockwise. They turn smoothly, too, without the clicking that a dive bezel has.
Other compass bezels are internal. You can turn these with a second crown that moves the bezel left or right.
The cool thing that these watches do is allow you to set the bezel to south or north. Once set, all the other directions are laid out for you.
They are excellent additions to a watch that you plan on using for outdoor activities.
Other Tricks For Using a Watch as A Compass
The Army Rangers only use the method described above in a pinch. The more accurate way they teach in their handbook uses a stick to cast a shadow.
Put a straight stick in the ground to get a shadow. Then you can place the watch on the ground and align the hour hand with the linear shadow cast by the stick. This is more precise and helps when you can’t see the sun in the sky, but objects still cast a shadow.
Another trick is using a digital watch with a similar method. If you know the time, you can draw an analog clock face on the ground. Draw the clock face so that the hour hand is in line with the shadow and visualize the clock in your head to determine where 12 o’clock is on the drawing.
From there, you can follow the same method above to find your south/north directional line.
Now that you learned how to use your watch as a compass, try it out! You can test it with a real compass or the compass app on your smartphone.
Remember, though, don’t rely on this method. If you’re heading into the woods for a long hike, bring a compass. Especially if you’re not familiar with the trail and your surroundings.
This is just one of the many things a watch can do apart from telling the time. If you want to learn about some of the other exciting things a watch can do, check out this article about watch complications.