Anything phenological has to do with the relationship between the climate and the seasonal cycles of plants and animals. A scientist might make phenological observations of monarch butterfly migrations over a span of ten years.
The adjective phenological is derived from the Greek phainein, "bring to light," and a root meaning "to shine." Phenological investigation brings to light the close ties between Earth's climate and cyclical movements or changes in certain organisms. A phenological study of apple trees would include the dates the first blossoms and apples appear, as well as the specific weather patterns that particular year.