Methods in a Radio Base Station (RBS) and in a terminal device for facilitating measurement at the terminal device are described. The method in the RBS comprises classifying frequency objects to be measured for a measurement task into a number of frequency object groups assigned with respective frequency measurement weights for determining measurement opportunities for the frequency objects; sending to the terminal device a first indication indicating the classification of the frequency objects into the frequency object groups. The method in the terminal device comprises receiving, from a RBS, a first indication indicating a classification of frequency objects to be measured for a measurement task into a number of frequency object groups assigned with respective frequency measurement weights; determining measurement opportunities for the frequency objects of the measurement task based on the frequency measurement weights.