What role does potassium iodide play in generating oxygen

Potassium iodide will act as the catalyst to decompose hydrogen peroxide into water and oxygen. A catalyst is a substance that participates in a chemical reaction and influences its speed without undergoing permanent change.

If the water vapor content stays the same and the temperature drops, then the relative humidity increases. its vise versa.if the water vapor content stats the same and the temperature rises, the relative humidity decreases. so, yes, i'd say that temperature and humidity have a strong relationship.