Rainfall data across Cambodia was compiled by Heng Chan Thoeum of the Cambodian government’s Ministry of Environment, Climate Change Department, in 2015 for a climate change study (link). To improve access to this information, this information has been input into Google Earth and is available for download as a KMZ file here. This data is available for free use; however, I would request that you cite this website if it is used in any formal work. Below is a screenshot of the rainfall data stored in the above file.
If you have questions, comments or problems using this data, please comment below.