SUMMARYThis paper analyzes the impact of external sources of information, conveyed by the frequency of risky events that vary across time, on the individual willingness to pay (WTP) for a reduction of mortality risk. We collected data from a contingent valuation (CV) exercise conducted in two waves (fall and winter) to examine whether individual WTP varied across periods that differed in the predominance of fatal accidents. Risk valuations were based on fatal snow avalanche accidents, that is, a type of risk with seasonal differences in occurrence. We found slightly lower but statistically significant mean WTP figures in the winter than in the fall sample because of time‐varying individual risk attitudes and, therefore, recommend controlling for these factors in risk assessment CV surveys. Copyright © 2013 John Wiley & Sons, Ltd.