Rainfall Gauge (Ted's Blog)

For my birthday, Susan gave me an electronic, wireless rainfall gauge. Not that it will get much use, but it should be pretty neat and beats the bucket on my front porch that I had been using to measure rainfall previously. I've always wanted one, ever since I wrote a paper in my college Hydrology course called "Rainfall Gauges: Our Funnel-Shaped Friends." This one is by Oregon Scientific so it should be compatible with my network of indoor/outdoor thermometers. In fact, it came with another remote thermometer, so now I have a backup (you can only have three).

It is a tipping bucket gauge, so the water never accumulates, but is just emptied. A bucket holds on millimeter of rainfall before registering it and then dumping it out of the bottom (it's actually two buckets on a teeter-totter). The reviews on Amazon were mixed to generally negative. It is a pain to set up. The gauge itself takes two AA batteries and I had to remove no fewer than 10 tiny screws to open up the battery compartment. Also there was something about calibrating the gauge, but I think really you are just levelling it. If you pour in 200 milliliters of water, it should register one inch of rain. When I tried it, it measured 0.9 inches. That may be because I poured the water in a little too fast. Realistically you would probably never get an inch of rain in 30 seconds. Also you want to make sure the teeter-totter inside is balanced. Holding it level I was getting about 20 drops from a leaking faucet on each side before either bucket would tip, which means the buckets are balanced. Using the dripping faucet, I set the gauge up over a bowl so that I could measure the water that was dumped. When the gauge showed 1 inch of rain I poured the contents of the bowl in a measuring cup and it came barely under the 200 ml line on the measuring cup. So I think I got a good one.

Now it just needs to rain.