Private diaries constitute a unique set of materials within climate change research in that they provide information both on past climate variability and on the ways that people live within, and interact with, climate. The fact that the observations within diaries are affected as much by personal experience as by physical conditions can render the derivation of robust climatic data problematic, and a number of techniques have been developed to generate quantitative or semiquantitative information from them. These include frequency counts of binary meteorological phenomena such as days with/without precipitation, content analysis techniques, proxies such as grain harvest dates, and statistical techniques that assume of some degree of continuity between the reconstruction period and the present day. The latter approaches can provide the most robust data, but can preclude direct comparison between past and present climates. Some studies attempt to increase reliability through comparison with other contemporaneous reconstructions, but this can create a potential for circular reasoning. As ethnographies, the methodological issues are less challenging. Most were highly personal documents and not intended for publication; diaries can therefore represent 'pure' ethnographies, representing an unbiased account of individuals' interactions with the 'weather world' and, in some cases, the ways that weather informed the character they presented to the world. Diaries can therefore exemplify individuals' highly personal engagement with weather and climate, reflective of a myriad of a number of social, cultural, political, and scientific narratives. Their use in climate research can therefore provide important contributions to current debates.