I am unsure how to explain thge difference but I can give you some examples. There will be times you can really use one or thge other but sometimes the two words can be interchanged. I have gotten myself into a sticky situation with making two appointments for the same time and day. The massive amount of snow made it a a difficult situation to maneuver in a small car. The circumstances that made it hard to get to work can be helped by preparations to leave. A struggling mother has some circumstances in which she will need help. Example of interchangeability: There are some situations/circumstances that can't be helped. both used in one sentence: The circumstances I have lived with have made it a sticky situation to get out of.