Editor;
As I am an old pensioner with time on my hands the noo, I have been logging rain fall in Pattaya/Jomtien from the Thai Weather Station. I have experience in setting up charts, from my previous life in Oil & Gas Recovery.
I get the information from the National Thai Weather Site, http://www.tmd.go.th/programs/uploads/cdms/RainAmphor/RainAmphorNational-en.pdf
I take an estimate between Pattaya/Jomtien; it’s an estimate, by me, and it’s not 100% accurate, but a rough history of past rain. I am not out there with a measured beaker. I am sure you aware, rain here can be localised.
Regards,
Matt Anderson