Track and Field 101: The Wind Gauge

A wind gauge, such as the device shown here, is used to quantify how much assist competitors receive from wind conditions. Photo by Alan Versaw.

For better or worse, we end up talking about wind a lot here on Colorado Track XC. I'm writing this article to add some transparency to how wind gauges work and the methods used to get the readings assigned to various heats and attempts in track and field.

First, there are two types of wind gauges in use--those that are remotely operated, like the device in the cover photo of this article, and other devices that must be started manually by a human operator, as in the image at the right.

For the most part, use of remotely-operated devices are limited to use in the straightway races (100 meters, 200 meters, and the 100/110 Hurdles). Not all meets will use a remotely-operated device, but it is becoming a little more the norm each year for the indicated races. 

The long and triple jumps also require wind readings, but--due to the nature of the events--these wind readings are almost always taken by hand-operated devices as shown at the right.

There are very definite protocols for how and when wind is measured during a race or an attempt.

In all cases, the device used to measure the wind (called an anemometer) must be placed four feet above the ground, parallel to the ground, parallel (in another dimension) to the straightaway or runway, at a prescribed distance from the straightaway or runway, and at a prescribed distance from the take-off board or finish line.

In the case of the long and triple jump, the anemometer shall be located within two meters of the runway and 20 meters from the foul line (or take-off board).

In the case of the 100, 200, and 100/110 Hurdles, the anemometer shall, once again, be withing two meters of the track (in this case, the inside edge of lane 1), and shall be placed 50 meters from the finish line.

For the long and triple jump, the anemometer shall be started when the jumper begins his or her approach and the recorded wind reading is an average of the next five seconds.

For the 100 and 100/110 Hurdles, the anemometer shall be started with the start of the race and be averaged over the next 10 seconds (100 Meters) or the next 13 seconds (100/110 Hurdles). For the 200 Meters, the anemometer should be started when the runners reach the 100 Meter start line (top of the straightaway) and be averaged over the next 10 seconds. 

Wind readings are rounded up to the nearest tenth of a meter per second. A rounded wind reading of 2.0 meters per second or less is considered "wind legal" and times from that heat or attempt may be used for records, state qualifying, and seeding purposes for future meets. 

So, if the average wind reading for a heat or attempt is 2.02 meters per second, that wind reading is rounded up to 2.1 meters per second. Any marks associated with that heat or attempt are used for purposes of meet placement and scoring but would not be allowed for records, for qualifying for state, or as seed marks for a future meet. And, truthfully, most anemometers do the rounding up automatically, so nobody ever knows if a wind reading for a particular heat attempt was 2.02 or 2.09. 

For conversion purposes, 2.0 meters per second is just a little under 4.5 miles per hour.

Any mark associated with a negative wind reading (into the face of the runner or jumper) is always legal for records, state qualifying, and future seed mark purposes.

Note that the only relevant dimension of the wind reading is the magnitude of the wind vector in the direction of the forward motion of the competitor.

As an example, let's suppose the finish straight of a track heads due south (most tracks are laid out in this manner). We will further suppose that a wind is blowing in a direction of 25 degrees south of west at a magnitude of 5.0 meters per second. Will marks registered under these conditions be wind legal?

To answer that question, we need to know how the anemometer aligned with the finish straight will read the wind. Essentially, the anemometer measures only the southward component of wind. If we break our 5.0 mps wind into westward and southward components using some basic high school trigonometry, we get a westward component of 4.53 meters per second and a southward component of 2.11 meters per second. That would register as a +2.2 wind reading and the effort(s) would be deemed not wind legal.

But, all sorts of other factors come into play. Winds don't blow for long at a steady rate. Winds surge, subside, and shift in direction. So, the next heat may have a wind of 4.0 meters per second in a direction of 27 degrees south of west. That would result in a wind reading of +1.9 meters per second, which would be wind legal.

Furthermore, even if the weather service were to set up a station next-door to a track, the wind readings at that station would not necessarily correspond with the wind readings from the anemometer alongside the track. For one thing, wind speed and direction vary considerably even over fairly small distances. For another, most high school stadiums afford a little sheltering effect from the winds. 

Moreover, if a track and field facility is thoughtfully designed, the long and triple jump runways will be aligned perpendicular to the prevailing winds. By doing that, you will turn most of the winds into crosswinds, which will rarely exceed the +2.0 limit in the direction of the forward motion of the competitor. 

Aligning straightaways in a direction perpendicular to the prevailing winds is another matter altogether, though. It is rare that a track is laid out with that consideration in mind. 

In most cases, a track is simply wrapped around a football field. And football fields are (in most cases, at least) purposely laid out in a north-south alignment to minimize the necessity of players (receivers, especially) needing to look at the ball without peering directly into the light of a sun near the horizon.

So, since a lot of Colorado's wind tends to come out of the north, we get a lot of wind-aided marks in the 100, 200, and 100/110 Hurdles. 

It may have already occurred to you that a heat of the 200 Meters could actually benefit considerably from the wind but still end up wind legal. If we assume our heat of the 200 Meters finishes in a southward direction, this might happen if we had a wind out of the east. A wind from the east would give considerable push to the runners through the curve of the 200 but would barely register on the anemometer because it measures only the southward component (the component aligned with the finish straight) of the wind.

That's just one of those situations we all have to learn to live with. Truthfully, though, it doesn't happen all that often.