This chapter considers the shifting meanings and capacities of American and British seasonal literature and media in light of anthropogenic climate change. Via two case studies, it compares seasonal work before and after widespread concerns about altered seasonal patterns in the United States and Europe. Beginning with a discussion of the seasonal aspects of Rachel Carson’s writing – most notably her sea trilogy – and its literary contexts, this chapter examines seasonal prose produced prior to the climate crisis. It also reflects on contemporary scholars’ tendency to revisit Carson’s work when ruminating on climate change, suggesting a nostalgia for seasonal reassurance. The chapter then turns to the contemporary production of seasonal media, using the BBC series Springwatch as a second case study. Placing Springwatch within a British tradition of seasonal broadcasting, it analyses the intersection of environmental and cultural seasonality in this series. As a show produced during a period of heightened climate anxiety, Springwatch actively works to generate seasonal data for climate research in the United Kingdom. In this sense, seasonal media unfolding within – and responding to – perceptible season creep can route seasonal sentimentality into the observation of phenological change.