Controls on the stable isotope composition of daily precipitation in Sydney Australia: 9 years of daily data, including Radon-222

•Daily and weekly rainfall stable isotopic data collected at Lucas Heights.•Local Meteoric Water line developed.•Factor controlling the δ values studied, from local to synoptic to large-scale.•Radon-222 investigated for synoptic and convective type analysis.•Isotope best correlation was with temperature, prior-rainout, rainfall amount and duration at the site.