The three solutions of ( ignores the dependence between T and X and responds with an estimate of pollutant concentration that assumes a precipitation level "averaged" over the entire observation period (e.g., over a year). Thus, while pollutant concentration can be expected to be lower during the wet season (simply because rain is more likely according to (8)), meteorological normalization predicts pollutant concentration for a given Julian date t via the all-year average precipitation probability.