ProperRainGuageSiting

Note:  These guidelines are based on those followed by the National Weather Service.

 

Precipitation monitoring can be very difficult to get accurate readings.  Proper placement is crucial in order to have reliable results.

Points to consider include:

• Gauges should not be located too close to obstructions such as trees and buildings, which may deflect precipitation due to turbulence.

• Do not locate in wide-open spaces or on elevated sites such as tops of buildings.  Do not mount on the side of a building.

• The best site is one where it is protected in all directions, such as an open grove of trees.

• The height of the protection should not exceed twice its distance from the gauge.  A general rule:  when you stand at your gauge site, you should be able to look up in any direction at a 45 degree angle and not see an obstruction.  If you must look higher than 45 degrees, then you're too close to the obstruction.

• The windier the gauge location is, the greater the precipitation error will be.

• NWS standard says the gauge should be 3 - 5 ft. off the ground.  The gauge will avoid having rain splash added to the totals.  This will also help protect the gauge from being knocked down by animals such as dogs and also prevents "non-precipitation" from entering the gauge.

• An example of an optimum site could be in the backyard of a farmstead where you have trees enclosing you in three directions, with the house protecting one side.  The gauge could then be mounted on an existing fencepost or a simple stake could be inserted into the ground.  You want to be careful of the distance from the trees and house, keeping in mind the 45 degree rule.

These considerations will help to ensure proper rainfall readings.  We must keep in mind that it is impossible to be 100% correct, but the more accurate you are, the more useful your readings will be.  If you have any questions or would like to help with placement, please contact:

Karly Osowski at karly.osowski@nd.nacdnet.net