I use the Canberra Airport weather station and the OS Evapotranspiration option for automatic weather adjustment appears to work well.
You still have to get your individual zone watering times right and I don’t think any system will work all year round. I tweak my watering times around the growing season here on Anzac Day when the frosts start, Melbourne Cup Day when the growing season starts in earnest and at Christmas when the heat waves roll through until the end of February. I have 6 dripper zones and one front lawn sprinkler zone.
In any case, rain here depends on you being lucky enough to be under a cloud when it dumps, so I run my rain delay manually when it actually rains in my back yard and only if we get more than a millimetre. You’re probably running rain tanks and a pump and I think using the auto EoT adjustment would work well for you over there.