Climate change education in biology classrooms requires teachers to address complex ecological systems, change over time, and the interaction between organisms and their environment. Here we present a biology lesson plan to teach students about the ecological consequences of climate change by learning about plant phenological shifts in mountain environments. This skills-based inquiry teaches students about quantitative methods for measuring ecological change, R programming, and scientific writing. Modular activities are integrated with discursive modules built for student-directed exploration of ecological data. The modules are designed for early-stage undergraduate biology students, but we organize materials by skill-based learning objectives so that instructors at levels from high school through undergraduate may also find useful resources in a variety of classroom contexts. Students will gain experience with hypothesis testing, reading primary scientific literature, data analysis, and structured technical writing. Assessments are based on formative, low-stakes writing assignments that are peer-reviewed and summarily combined into a final technical report describing phenological change in montane wildflowers in the Rocky Mountains. We provide all necessary background information pertaining to the case study used in this paper, as well as recent popular science articles, fully reproducible R scripts, and pre-populated data sheets for easy analyses. Our aim is to support teachers who wish to discuss measurements of change over time, evidence-based climate change science, and science communication. Primary Image: Ecologists (left to right graduate student Ellen Wright, middle school teacher Rhyne Gulley, college student Ellen Warmerdam and graduate student Fatima Alcantara) collecting phenology data from focal species at the Rocky Mountain Biological Laboratory in Gothic, Colorado. Data from this long-term phenology project are used in this teaching resource for guided data analysis and scientific writing about climate change.