This latest update compares the three decades between 1981 and 2010 to the 30 years prior, between 1951 and 1980.
Globally, the clearest index shows an increase in the number of above-average warm days.
Broadly speaking, rainfall extremes have increased in the west and decreased in the east, but trends vary by season.
In New Zealand, temperate regions experience significantly more summer days and northern parts of the country are now frost-free.
Across New Zealand, the heat available for crop growth during the growing season is increasing, which means wine growers have to shift varieties further south.
But in parts of southeast and southwest Australia, frost frequency has stabilised, or even increased in places, since the 1980s.
The higher number of dry, clear nights in winter, favourable for frost formation, has cancelled out the broader warming trend. »