This article examines the past and potential contributions of Pliny the Elder’s Natural History (NH) on the subject of Roman perceptions and experiences of environmental change. It asks in particular how classicists, archaeologists, and environmental historians can responsibly use the NH as a source on ancient climate. First, it briefly reviews relevant topics in the paleoclimatology of the Roman world, a rapidly advancing discipline enabling the identification of ancient climate changes with increasing precision and confidence (I). The article then turns to the reliability of Pliny as an authority on ancient climate by examining his accuracy, objectivity, and use of source material in literary and historical context, including his rhetorical goals, which have gone understudied until quite recently (II). A close reading of passages on environmental and climate change follows, highlighting areas in which Pliny’s observations are at odds with his source material. The examples discussed demonstrate the importance of phenology (III) and meteorology (IV) in Pliny’s encyclopedic account of the natural world, one characterized by anthropocentrism, pragmatism, and an emphasis on local knowledge. The evidence for ancient climate change is plentiful but not conclusive on the details and timing, and further studies will continue to refine local records. Rather than presenting a synthetic reconstruction based on Pliny’s observations, I argue that his encyclopedia offers an untapped resource on ancient climate and weather, not only by providing evidence of climate change, but also by recommending increased attention to seasonality, agricultural communities, and the lived experience of agricultural labor in order to better understand the effects of climate change on ancient populations.