The El Niño–Southern Oscillation and daily temperature extremes in east Asia and the west Pacific

The numbers of warm nights and hot days, across most of the east Asia – west Pacific region, increase substantially in the year after the onset of an El Niño event. The number of cool days and cold nights tend to decrease, although the relationship with El Niño is weaker for these variables. The relationship is confounded, for warm nights and hot days, by a strong increasing trend in the numbers of extremes not matched by a trend in the El Niño. Removal of this trend leads to even stronger correlations with the El Niño. Strong correlations exist between some of the extremes indices and an index of the El Niño – Southern Oscillation in months prior to the occurrence of the extremes, indicating that predictions of the frequency of extreme temperatures across the region should be feasible.