When in rain delay, the status screen it should say why we are in rain delay (METAR, NOAA, Local sensor, or any combination of those), this can be gotten by digging through the logs, but it's not easy. If the system enters raid delay due to one source say NOAA forcast, but then switches to another source METAR or local sensor, there is no way to tell what source is causing the system to be in rain delay.
When in rain delay, it should be possible to have several severities of rain delay (such as reducing the watering amount by X% or have X determined by severity), etc...