In this study, forecast skill over four different periods of global climate change (1982–1999, 1984–1996, 2000–2018, and 2000–2014) is examined using the hindcasts five models in North American Multimodel Ensemble. The deterministic evaluation shows that forecasting skills Niño3.4 Niño3 indexes are much lower during 2000–2018 than 1982–1999, indicating previously reported decline continues thro...