Abstract: A system and method for making a decision of whether to carry additional fuel on an aircraft for a particular flight based on a forecast, such as for low visibility and ceiling. Preferably, observations-based probabilistic forecasts are utilized. The forecast probability of the weather at the planned aerodrome being below a prescribed minimum level is calculated using statistical regression analysis of past data. An optimal probability is estimated using cost parameters on an individual flight bases. If this forecast probability is greater than the optimal probability for a particular flight, then extra fuel is carried by that flight. This is in contrast to current practice whereby the same categorical forecast is applied to all flights. The combination of improved short-term forecasts and identification of optimal forecast probabilities minimizes the financial impact of errors and weather forecasts on airline operations thereby providing a superior financial outcome.