This report describes how the climate of Casco Bay watershed in Maine has changed over the past century and how the future climate of the region is likely to be affected by human emissions of heat-trapping greenhouse gases that are warming the planet. Overall, the region has been getting warmer and wetter over the last century, and these trends have increased over the last four decades. To generate future projections for Portland, Farmington, and Lewiston, simulated temperature and precipitation from four climate models were fitted to local, long-term weather observations. Unknowns regarding fossil fuel consumption were accounted for by using two future scenarios. The scenarios describe climate in terms of temperature and precipitation for three future periods: the near-term, 2010-2039, mid-century, 2040-2069, and end-of-century, 2070-2099. All changes are relative to a historical baseline, 1970-1999. Some future changes are inevitable, so smart choices must be made to ensure our society and our environment will be able to adapt to coming change. But with prompt action, many of the most extreme consequences of climate change could be avoided or their worst impacts reduced.