When using separate worldinfo and calling /jed weather on a custom dimension (or setting it as rainy in the config) Dinamic Surroundings is not notified, so the rain effect is not visible in that dimension

Dynamic Surroundings has an API to fire the WeatherUpdateEvent for it, so I think just triggering that event from JED if DS is loaded should fix it

https://github.com/OreCruncher/DynamicSurroundings/blob/master/src/main/java/org/blockartistry/DynSurround/api/events/WeatherUpdateEvent.java#L77