Which type of forecast is based on long-term averages?

The type of forecast that relies on long-term averages is the climatological forecast. This approach uses historical weather data to predict future weather conditions based on the average climate patterns of a particular region over an extended period, typically 30 years. By analyzing this historical data, climatological forecasts can give a general idea of what weather conditions can be expected during a specific time of year.

This method is particularly useful for long-term planning and understanding seasonal trends, as it provides insights based on patterns observed in the past. In contrast, nowcasts focus on predicting weather conditions in the very short term (typically less than six hours), short-range forecasts cover a few days ahead, and outlooks provide broader predictions for several days to weeks in advance, often considering various models and current atmospheric conditions rather than solely relying on historical averages.