Due to the sparsely located World Meteorological Organization (WMO) data sites in some areas of the world (e.g., polar regions), non-traditional datasets such as indigenous knowledge are sometimes used as an indicator of climate change. Local indigenous knowledge depends on human memory of climate, yet the accuracy of this knowledge has not been checked in peer-reviewed literature. The purpose of this interdisciplinary study is to determine how accurate recollections of climate are and what may influence those memories. This pilot study, combining climatology with psychology, examined recollections of climate in the Denver metropolitan area, a WMO location, in periods varying from two to twenty years. The approximately 400 respondents answered questions about climate, focusing on summer (June, July, August) and winter (December, January, February) air temperature and precipitation trends, and various factors (e.g., gender, education, occupation, beliefs about climate change) that may influence memories of climate via an online survey. Results were compared to the actual meteorological conditions recorded at the Denver-Boulder National Weather Service Forecast Office and at the Western Regional Climate Center.

When asked about climate data two years ago, most respondents recalled the temperature trend (e.g., higher, about the same, or lower), however, participants did not agree about precipitation amounts (e.g., more, about the same amount, or less). Approximately equal numbers of respondents reported more precipitation as respondents who reported less precipitation for summer two years prior. Other factors (e.g gender, education, occupation) did not seem to significantly influence weather memories two years prior to the survey. When asked to recall climate 20 years prior to the survey, more participants (up to 44%) reported that they did not remember. Of participants who did select a trend, the temperature trend was again more accurate than the precipitation trend as compared to instrument data. Other noteworthy results include that respondents were more confident that summer air temperatures are higher now than they were about winter temperatures changing over time. But, respondents were more confident that the Denver metropolitan area used to receive more winter precipitation than they were about the change in summer precipitation over time. When looking at gender and climate recollections, results showed that females were more likely to say that temperatures were cooler in the past, regardless of season, and that there used to be more precipitation, again regardless of season. Males were more likely to select “no change”. The role of factors that had a significant effect on responses, including current beliefs about climate change, time spent outdoors, and education, will also be discussed.

Several questions raised by this study include how do recollections of climate determine a person's response to a hazardous weather event? How can managers and policy makers use this information to effectively warn the public of hazardous weather? And, how can climatologists use this information to improve models?