Ambient Weather Support

Wind Speed Or Wind Gust Appears To Read Low.

This is a very common complaint with weather station owners, regardless of model numbers or manufacturers (from the low cost $100 weather station to $1000+ weather stations). Many of the units returned to us meet their accuracy requirements based on a constant speed fan test.

Here are some things to look for on how wind speed and wind gust are defined, proper installation techniques and wind speed perception in general.

  1. In general, if you are getting some drag or bearing failure, the cups will come to an abrupt stop in low winds. If the wind cups coast down to zero wind speed, this signifies your bearings are fine.
  2. Most weather stations average the wind speed over the update period and provide the peak gust in the update period (defined as wind speed and wind gust). Average wind speed, from a perception stand point, is much lower than wind gust, because wind speed is never a constant. Most customers identify with wind gust (when branches fall down for example). Thus, it may be beneficial from a perception stand point to focus on the gust and not the speed.
  3. Most weather stations have a lift off speed (overcoming static friction). This lift off speed can be about 2 miles per hour. This is rarely an issue, because the average wind speed tends to average out through sampling wind speeds less than 2 miles per hour.
  4. Proper installation is very important. The wind gauge should be mounted four times the distance of the differential height of the tallest obstruction.

    Example: House = 20 ft tall, pole = 5′ tall.

    Distance = 4 (20 – 5) ft = 60′ away from house.

  5. Compare your weather station to other stations in your area.

    An excellent guide is to visit:

    wunderground.com

    And enter your zip code. Compare your wind speed and gust with other stations in the area by scrolling to the bottom of the search results page until you see “Nearby Weather Stations”.

  1. Here is a general guide in what occurs on land as a function of wind gust:

 

Wind Gust (mph) WMO Classification On Land
< 1 Calm Calm, smoke rises vertically
1-3 Light Air Smoke drift indicates wind direction, still wind vanes
4-7 Light Breeze Wind felt on face, leaves rustle, vanes begin to move
8-12 Gentle Breeze Leaves and small twigs constantly moving, light flags extended
13-18 Moderate Breeze Dust, leaves, and loose paper lifted, small tree branches move
19-24 Fresh Breeze Small trees in leaf begin to sway
25-31 Strong Breeze Larger tree branches moving, whistling in wires
32-38 Near Gale Whole trees moving, resistance felt walking against wind
38-46 Gale Twigs breaking off trees, generally impedes progress
47-54 Strong Gale Slight structural damage occurs, slate blows off roofs
55-63 Storm Seldom experienced on land, trees broken or uprooted, “considerable structural damage”