This is an excellent paper that applies the three-cornered hat (3CH) and four-cornered hat (4CH) methods to estimate the uncertainties (random error variances) of four precipitation datasets. It is acceptable for publication after the authors consider some relatively minor changes that would improve the clarity of the paper. My full review with suggested edits is included as a Supplement.

This study explores the estimation of random error variance in four gridded precipitation datasets sourced from various natural sources using the triangulation method called the Four Cornered Hat (4CH). In my assessment, the paper falls short of the standard expected by the Journal of HESS and would benefit significantly from a major revision. My main concern is the ambiguity regarding whether the variant of the 3CH, the 4CH, is an innovative aspect of this study. My full review is included as a Supplement.