The passing of seasons, as gauged by annual events or phenophases in organisms’ life cycles, is arguably one of the most pervasive environmental variations on Earth. Seasonal timing, or phenology, are observed in flowering and other stages of plant development, animal migration and reproduction, hibernation, and the seasonal activity of cold-blooded animals. Moreover, the timing of these events are changing due to recent climate change. The impacts of these shifts can be seen at many scales, from the physiology of individuals to community-level interactions to ecosystem functioning. Also, as an important aspect of life history, phenology is an object of natural selection; depending on the organism and timescale, phenology can be shaped by evolution. In addition to its direct ecological significance, phenological observations, research, and education are attractive entry points for enhancing ecological insight and understanding in other sciences and in the public. Nearly everyone can relate to phenological events, so that the passing of seasons as expressed in the blooming, leafing out, and senescence of plants and the arrivals and departures of recognizable species play a temporal role not unlike the place of charismatic megafauna in habitat management. Thus phenological observations (by citizens and scientists alike) and research (even when it comes from the most academic sources) routinely attract public attention in ways that motivate broad ecological understanding. This session contains an integrated set of talks that describe research, applications, and outreach efforts that use phenological measures to enhance public and scientific ecological understanding and thought. A large number of citizen-science phenological observing groups, like Monarch Watch, Nature’s Calendar, and the USA-National Phenological Network’s Project Budburst, have developed from grassroots interest in the natural world. Representatives from some of these programs will share experiences and lessons from citizen-scientist observations. Research into drivers and consequences of phenological variations has provided results that make existence and implications of biodiversity, ecosystem services, and climate change more visible and understandable to citizens and non-ecological scientists alike. In particular, this session will describe the emerging role of phenological understanding in several major fields, such as conservation biology, invasive species management, and human allergies. Key and highly visible research efforts will be presented with discussion of how they have influenced public discourse and understanding of climate change in particular and ecological science in general.