Calibrate a G2-RAIN

The G2-RAIN’s included rain gauge comes factory calibrated. However, to ensure the most accurate measurements this calibration should be verified regularly.

G2-RAIN diagram



    1. Remove the siphoning tipping bucket by loosening the three connection bolts and lifting up. Follow the guide below to learn how to remove the siphoning tipping bucket.
      1. Install and Remove the Siphoning Tipping Bucket 

G2-RAIN siphoning tipping bucket


    1. Remove the rain gauge from the G2-RAIN-RTU base by unscrewing the (3) 9/16″ bolts.


    1. Remove the tipping bucket leads from the reed switch and the other screw holder.

Remove tipping bucket lead from the Reed switch


    1. Loosen the cable nut and carefully, one at a time, remove each tipping bucket lead through the cable gasket.
      1. Set the G2-RAIN-RTU aside.

Remove the tipping bucket leads one on top of the other

Carefully remove the leads through the cable gasket


    1. Level the gauge using the bulls-eye level

Level the bulls-eye on the rain gauge



    1. Move the adjustment screw (under the opposite bucket) all the way counter-clockwise.
      1. The bucket over that screw should lie flat.

Rotate the adjustment screw for the opposing bucket counterclockwise

The bucket should lie flat.



    1. Using a syringe and a mass balance, weigh out the standard amount of water necessary to achieve a tip for the specific tipping bucket model by following the table below.
      1.  While the syringe is empty on the scale, zero the scale to correct for the mass of the syringe, and then add the proper water mass.
Model Number CalibrationGrams per Tip
G2-RAIN-0.01”0.01 inch of rain8.40 grams
G2-RAIN-0.1mm0.1 mm of rain3.31 grams
G2-RAIN-0.2mm0.2 mm of rain6.62 grams
G2-RAIN-0.5mm0.5 mm of rain16.54 grams
G2-RAIN-1.0mm1.0 mm of rain33.08 grams



    1. Slowly release water into the raised bucket side.

Slowly fill the raised bucket side with water


    1. Once all of the water has been released, slowly spin the adjustment screw (that was lowered in step 4) clockwise until the bucket tips.
      1. This adjustment will force the bucket to tip whenever that specific mass of water is pooled into the bucket.

Rotate the screw below the opposite bucket until the bucket filled with water tips


    1. Repeat for the other bucket


    1. Confirm the calibration by replacing the outer cover and letting a known amount of water flow through the gauge until 5 tips have occurred for each bucket.
      1. Before beginning the measured test, let several tips occur to ensure the assembly is wet.


    1. Measure the output from each bucket separately.


Make any necessary changes to the adjustment screws ¼ turn at a time until the expected measurement is achieved