Pink Lake Lookout, GatineauGatineau experiences noticeable climate changes throughout the year. The close proximity of the southern part of the watershed to the Ottawa River results in a hot and humid summer making Gatineau the warmest climate in Quebec with temperatures around +25°C (+76°F). It has an average of 2,059 hours of sunshine per year. Fall and spring are pleasant though quite cool and cloudy. The rainfall is minimal and September is the wettest month with the average rainfall around 83 cm (3 in). Winter can be very cold, the average low is around -13°C (9°F) and it is not unusual for local snowstorms to bury cars. There is a marked climatic variation between the north and south of the watershed.

Projections for the Ottawa-Gatineau region suggest increased climate variability as well as more precipitation, heatwaves and freezing rain events. Rising temperatures will force wildlife to shift their ranges northwards, stressing species adapted to cooler temperatures and significantly altering both the extent and composition of ecological communities. As habitat becomes less suitable for some wildlife, habitat loss will likely increase their risk of extinction.

Two other serious threats of climate change are the increased risks of wildfires and species invasions for example, forest insects. Both will threaten the watershed's biodiversity and the health of its ecosystems.