Urban forests provide important services to residents such as reducing air pollution, decreasing storm water runoff, and mitigating temperature extremes. Many of these benefits are dependent on when and how long leaves are on the trees, which is determined by their leaf phenology. The timing of phenological events is expected to shift with climate change, but the direction and magnitude are still uncertain. In Mediterranean climate regions, precipitation has been shown to be an important environmental cue in natural ecosystems; however, it is unclear whether this also applies to urban landscapes where additional water resources are common. To investigate this process, we used high resolution PlanetScope satellite imagery from 2018 to 2024 to monitor more than 35,000 species-identified trees in Santa Barbara, California. We successfully detected seasonal NDVI changes of individual trees, including evergreen species which we validated with field observations. In our image time series, 81.8 % of the deciduous tree population and, notably, 69.1 % of the evergreen tree population had at least one annual phenology cycle that was detected. Overall, trees were sensitive to precipitation with spring rain delaying the end of the season by 2.25 d/cm on average across species. Warm fall temperatures delayed the green-up date whereas warm winter temperatures led to an earlier green-up. These results build upon methods to study the diverse urban forest of semi-arid climates and deepen our understanding of how changing climatic patterns may affect the leaf phenology of these species.