A windsock is a simple gadget that allows us to estimate the wind’s speed and direction roughly. But which data does it provide, and how should we read it?
There is an old discussion on whether the wind is tangible or intangible. You cannot exactly touch it, but can feel it; you cannot see it, but you can measure it.
The truth is that humans have found a way of giving it a visual representation of its strength and direction.
Today, there are several scientifical and empirical methods for measuring and checking wind speed and direction.
Among them are beach flags, the wind compass, the wind vane, the wind compass, hand-pouring sand, the old-school wet finger technique, and the timeless Beaufort Wind Force Scale.
They can all help you determine roughly the wind conditions at any given moment, even though they carry a high margin of error.
On the other hand, the anemometer is the most accurate tool for measuring wind in real time.
Nevertheless, an in-between method could provide fairly accurate data on the current wind speed and direction conditions.
The answer is the windsock, a wind measurement mechanism used for the first time by 19th-century naval ships.
Nevertheless, the Japanese were the first to invent it a few centuries ago, even for different purposes.
What is a Windsock
The windsock is a white and red orange-striped conical tube generally made from nylon fabric or a woven textile to estimate wind speed and direction.
The meteorological instrument is usually found in airports, highways, racetracks, industrial facilities, chemical and nuclear plants, offshore oil rigs, beaches, marinas, and often windy locations.
It is also a simple and helpful tool for firefighters to analyze the direction of smoke and fire and for local authorities in the event of accidents involving the release of toxic gases.
The windsock, also known as wind cone, is an easy-to-read visual indicator of where the wind is blowing and how strong it is.
When it comes to revealing the direction, a windsock pointing due west indicates an easterly wind.
So, remember that the direction of the wind is the opposite in which the wind cone is pointing.
As for wind speed, users must pay attention to the windsock’s angle relative to the mounting pole.
In high winds, the colored conical tube flies horizontally; if there’s low wind or no wind, the giant sock will droop and deflate.
High-quality windsocks should not become rigid in cold weather in order to keep them responsive even to the lowest wind.
These windsocks are often UV protected and urethane coated to retain the color and provide fade resistance.
After being cut, the white and red-orange stripes are sewn with reinforced double-stitched hems and incorporate heavy-duty brass grommets.
And yes, you can make a working windsock as long as you get the figures right.
The size of the sock may vary, but there are specific diameter-length ratios that should be followed. They are as follows:
- 4” Diameter > 3/8” Length;
- 6” Diameter > 9 1/2” Length;
- 8” Diameter > 12 1/2” Length;
- 10” Diameter > 15 3/4” Length;
- 13” Diameter > 20 1/2” Length;
- 18” Diameter > 28 1/2” Length;
- 20” Diameter > 31 1/2” Length;
- 24” Diameter > 37 3/4” Length;
- 36” Diameter > 56 1/2” Length;
The Windsock Speed Chart
As we’ve seen, wind direction is relatively easy to determine.
The observer should look at the direction the windsock is flying to know where the wind is blowing from.
When it comes to wind speed, there’s something users must memorize.
Windsocks feature five stripes – three bright red-orange and two white stripes.
You’ll notice two red-orange stripes on both ends, followed by two white stripes and another red-orange stripe in the middle.
But how can we know if it’s three or over 15 knots of wind?
It’s relatively easy – each stripe flying parallel to the ground adds three knots of wind speed.
- 1 stripe = 3 knots (3.5 mph / 5.6 km/h);
- 2 stripes = 6 knots (7 mph / 11.1 km/h);
- 3 stripes = 9 knots (10.4 mph / 16.7 km/h);
- 4 stripes = 12 knots ( 13.9 mph / 22.2 km/h);
- 5 stripes = 15 knots + (over 17.3 mph / 27.8 km/h);
Here’s a graphic representation of all windsock speed measures.
The height installation of windsocks depends on the purpose.
It should be placed in a high position if it has to indicate the wind direction of, for instance, a gas leak.
If the wind cone has to indicate the wind direction for cars, or if there are a lot of buildings close to each other, then it should be mounted on a low level.
Although this is the most widely used standard, other conventions are based, for instance, on the windsock’s angle – in degrees – relative to the mounting pole.