The main subject of this thesis is the determination of climate risks to objects in museums on the basis of measured or simulated temperature and relative humidity data. The focus is on the quantification of climate related risks for the preservation quality of indoor climates in Dutch museums. The effect of the indoor climate on degradation processes is described. The three processes are biological, chemical and mechanical degradation. Indoor climates are described by statistical parameters to provide information like averages, short time fluctuations and seasonal fluctuations for temperature and relative humidity. The general climate risk assessment method is introduced, which analyzes climate data by determining the percentage of data that fits into each ASHRAE climate class. It is concluded that this method is easy to use and that it provides more reliable results than the general climate risk assessment method.