Urban forests are important for ameliorating urban heat loads and the urban microclimate may have an impact on tree phenology. Understanding these interactions is important to urban planners to select suitable trees for the urban forest. For one year we tracked leaf cover, flowers and fruit of 22 tree species in Bang Kachao Peninsula and explored correlations between phenology and climatic factors. Tropical lowland trees, with exception of mangroves, had reduced leaf cover in the dry season. Mangroves flowered and fruited throughout the year as compared to 1-3 times a year for tropical lowland forests. Positive correlations were found between flowering of Diospyros decandra with temperature; flowering of Aglaia cucullata and Elaeocarpus hygrophilus with rainfall; and fruiting of Dillenia indica and Diospyros malabarica with rainfall and relative humidity. We intend to apply tree phenology results to urban forest restoration and to monitor any adaptation to climate change for future mitigation strategies in tropical urban forests in Thailand.