How to judge wind speed: Professional tips and tricks
For long-range shooters, it’s important to apply precise compensation when it comes to shooting in a windy environment. To do that, you must be able to determine the wind speed along with its direction which is not easy. In the case you know nothing about wind compensation and could really use some help, this article is for you. Down below, you would find a comprehensive guide on how to judge wind speed along with a couple of helpful tips and tricks. Take a look at them and you should master the skill in a blink of an eye.
The principle of wind compensation
As mentioned above, there are 2 things you need to know in order to make accurate assessments: Direction and Speed. For most of the time, to obtain the necessary information, all you have to do is to check your surroundings. Just observe how the trees, the leaves or the grasses are moving and you could easily determine the wind direction. Many shooting ranges are even equipped with a couple of wind flag to help the shooters to interpret the direction of the wind as well. After you figure out the direction of the wind, you could either adjust your scope setting or move your aim accordingly.
About the wind speed, you could also use the nature to your advantage though you may want to consider using specialized accessories. If you feel a light breeze on your face, the wind speed is about 3 – 5 mph. A wind speed of 5 – 8 mph should be able to blow the leaves on nearby trees. When the speed of the wind reaches 8 – 12 mph, the surrounding dust would kick up. In the case several small trees are being bent and swayed by the wind, you probably are dealing with a wind speed of 12 – 15 mph.
You could also estimate the speed of the wind by “reading” the mirage which requires a conversion chart and good judgment. The idea is to get a crisp target image with your scope first and rotate the parallax knob back a quarter turn. By comparing the mirage you receive with a conversion chart, you should be able to figure out the wind speed. One major benefit of this technique is that you don’t have to worry about wind angle because you always a see a full value mirage. Do remember not to focus the parallax knob beyond the target though since that will flip the mirage and lead to false reading.
Target shooting in windy condition
The compensation doubles as the speed of the wind doubles, for example, 10 mph compensation is half that of 20 mph compensation. For a wind with 10 mph speed, the necessary compensation is twice that of a 5 mph. Shooting distance would not follow this formula though: The wind compensation at 600 yards is going to be more than twice the compensation needed at 300 yards. This is due to the fact that as the bullet travels, it will slow down and start to plunge downward. Therefore, the effect of the wind on the bullet will only get worse as the bullet travels further and further.
So how could you apply necessary compensation base on the information about the wind speed and direction you just obtain? Well, there are many formulas in circulation but here is a popular one, you could use it to good effect in most of the case.
Range (Yard) / 100 x Speed (mph) /X = Windage adjustment (MOA)
X will change depending on the shooting range
- X = 15 (Range < 500 Yards)
- X = 14 (500 Yards < Range < 600 Yards)
- X = 13 (600 Yards < Range < 800 Yards)
- X = 12 (800 Yards < Range < 900 Yards)
- X = 11 (900 Yards < Range < 1000 Yards)
For an example, if the distance between you and your target is 300 yards and there is a 10 mph wind, the windage adjustment will be: 300/100 x 10/15 = 2 MOA.
The effects of the terrain
In general, it’s rare for the crosswind to be constant and linear where the terrain is a mix of different features. Winds tend to flow parallel to the ground which means hills, rocks and trees would have a considerable influence on their behaviors. For most of the time, winds in mountainous regions are highly likely to have upwellings, backwashes, swirls and plunges. As a result, it’s helpful for you to have a good understanding of the geographic of the shooting area.
Several situations also require more complicated compensation compared to normal such as shooting between areas that have different wind speed. For example, your target may be located in a place that is shielded from the wind but you are in a completely open area or vice versa. In some cases, both you and your target are shielded from the wind but there may be a lot of wind between you and your target. Al it takes is one unexpected gust of wind and your bullet will go astray so think carefully before you squeeze the trigger.
Aiding accessories and similar items
It’s not like everyone could remember all the numbers involved so many shooters turn to specialized accessories to take care of the wind compensation. Some people fabricate their own range card so they could deduce the wind drift at different distance precisely and effortlessly. Because personal range card usually incorporates the bullet drop of the shooter preferred ammunition into account, their effectiveness is higher than commercial tools. Of course, you have to go through quite a bit of round and invest in order to make a usable range card and that will require a lot of time and effort.
In the case you don’t exactly have the patient to produce your own range card, there are always other options for you to choose. A combination of a wind speed indicator (such as Skymate) and a wind compensation disc (such as Windy Disc from Open Season) should be sufficient in most the case. These items are available at a reasonable price and they are quite easy to use. Generally speaking, aiding accessories and similar items are the most accurate way to obtain information about the wind characteristics