How does a Tipping Bucket Rain Gauge Work?

The tipping bucket rain gauge is the most common way to measure rainfall in electronic weather stations such as the WS-2315 and WS-2308 , and in the WS-7038 wireless rain gauge.

A tipping bucket rain gauge consists of:

• a funnel to collect rain drops
• a very carefully calibrated pair of buckets on a see-saw to measure the rain drops
• a sensor to detect the bucket tipping
• a weather station to display the amount of rain fall measured

Rain that is collected by the funnel falls into one of the small buckets. These buckets are carefully calibrated so they will hold an exact amount of rain or precipitation, usually the equivalent of 0.001 inches of rainfall (0.03 mm). The buckets are balanced on a fulcrum so when one bucket fills with rain, the lever tips. The second bucket moves under the funnel while rain collected in the first bucket empties out the drain hole. Each time the lever tips, a small magnet on the lever moves past a reed switch sending a signal to the weather station. By counting the number of signals from the reed switch, the weather station can count how many times the buckets have been filled to calculate the total rainfall.

Installing a Tipping Bucket Rain Gauge

There are a few important considerations to bear in mind when installing a tipping rain gauge to ensure the accuracy of your readings.

Firstly, the gauge must be positioned on a flat surface. If the surface is not flat, the buckets won't be balanced properly on the fulcrum and won't tip when they fill with rain. Use a level to ensure the surface is flat, when installing your rain gauge, then attach it securely to this surface so it cannot move. This is important: the rain gauge will not be accurate if the surface is not level.

Secondly, don't mount the rain gauge on a surface that vibrates, such as a porch or fence. Vibrations can cause the gauge to tip even when there is no rain causing an inaccurate measurement.

Thirdly, keep the rain gauge away from buildings and trees that might shelter it from the rain or drip water or leaves into the collection funnel. To get the most accurate result, the rain gauge should be placed in an open space away from buildings and trees.

Following these, and the instructions that came with your tipping rain gauge, will help ensure you get the most accurate results possible from your gauge – good luck and good weather!