Stochastic simulations of wildfire occurrence and growth have become an integral part of both wildfire incident management and land management planning applications. The FSPro simulation system, implemented in the online Wildland Fire Decision Support System (WFDSS), acknowledges that weather inputs to wildfire growth modeling systems—wind and fuel moisture—are uncertain beyond just a few days, and therefore simulates the range of potential growth possible given the distribution of wind and fuel moisture inputs. The FSim wildfire occurrence and growth simulation system, like FSPro, acknowledges uncertainty in weather inputs, but also accounts for uncertainty regarding the likelihood of wildfire starts, where they are likely to occur on the landscape, and their duration. The MTT function of FlamMap5 relies on a single problem-fire weather and duration scenario, but acknowledges uncertainty in where a problem-fire may ignite on the landscape.