Time horizon is a point in the future or past where the visions, scenarios, projections or predictions are set. The time horizon in foresight is typically mid- to long term ranging from 5 to 50 years. The time horizon should ideally lie beyond the normal planning horizons of the decision makers involved, but close enough that it could still be influenced by today's decisions.
Dammers, E. et al. 2013. Scenario’s maken voor milieu, natuur en ruimte – een handreiking. Den Haag