Weather, Climate and Temperature

Weather is the condition of the atmosphere, such as temperature, humidity and rainfall, at a particular place over a short period of time, i.e., a few days. For instance, a weather forecast usually goes a few days ahead. Climate refers to the weather pattern of a place over a long period, i.e., a few decades or more. A well-known term is "climate change".

In load forecasting, the most frequently used weather variable is temperature. A temperature station is often called weather station, though a weather station may measure many variables beyond temperature.

Many utilities also include other weather variables as predictors in short term load forecasting models, such as humidity, wind speed and cloud cover. In reality, because it is difficult to forecast these predictors with good accuracy, there is a trade-off between the information gained by adding these additional variables and the noise introduced by their forecast errors. I always go with the principle of parsimony. Unless rigorous tests have been conducted showing the benefits of adding additional variables, I would try to keep the model as lean as possible.

Back to Load Forecasting Terminology.