We had some fairly heavy wind here recently and I noticed, as is usually the case, the water in the toilet would move. I thought we could probably use Python and some sort of IoT or Pi device to measure the “waves” and give an estimate of the wind speed.
You’ll have to factor in the diameter of the sewer vent on the roof, its height over the water level in the toilet, and allow for any number of bird or squirrel carcasses lodged in it.