This study examines how the timing of extreme events affects annual gross primary production (GPP). The results show that extreme climate events occurring at the beginning of the growing season have a significant impact on GPP. Such events can have both positive and negative effects. Using an explicable LightGBM model, we identified thresholds and tipping points where the transition between positive and negative effects occurs. For example, our results indicate that prolonged heat waves with temperatures above 31ºC in the early growing season lead to a significant decrease in GPP.