Today, Season Watch uses a reference database to flag for errors in citizen submissions (data collected by the citizens). However, due to rapid changes in the climate, trees are going through their seasonal phases earlier or later than anticipated, so citizens’ inputs may not actually be inaccurate. Season Watch would like us to assess and understand the shifts of seasonal behavior of common trees by comparing citizen submitted tree data against the reference database. This is achieved by comparing citizen-submitted observations of tree phenology (such as leafing, flowering, and fruiting times) with a historical reference database. The goal is to identify discrepancies, infer actual shifts over a decade, and update the reference database based on emerging patterns to improve its accuracy and reliability.