I have found the original rain gauge for meteostatins, specifically the WH-xxx, Hadexx and their AliExpress counterparts, to be unsatisfactory. Although there have been some design improvements, they still fall short of expectations. The first versions of the rain gauge lack sufficient depth, and even the newer versions with higher walls are not sufficiently accurate so I have to made extension to it.

To address these issues, this model has been developed, which not only resolves the accuracy concerns but also remains compatible with the stock station. I have extensively tested it on numerous stations, so everything is properly tested.

This extension significantly increases the gauge's triggering frequency, precisely 3.971544 times more than the stock version. Setting it to 4x is good enough. While I don't have the measurement for imperial units, the original values were 0.2794mm of rain per momentary contact closure. And the new value is 0.0703mm of rain causes one momentary contact closure.

I conducted side-by-side tests with the original gauge, and the results were an exact match.

Glue needed :) 

This version is for 20mm rod, I also has a 22mm version here (in progress)