The Blue Skies El Nino 2026-2027 Preparedness Report, released this week, shows the weather phenomenon is now tracking to peak in late summer 2026-2027, and is in the same category as 1972-1973, 1997-1998 and 2015-2016 — three of the strongest El Nino events on record.
Blue Skies Weather meteorologist Tony Trewinnard said it could mean very wet and windy conditions for some areas, and possible drought conditions in others.
It was expected to have a significant impact on agricultural, horticultural and viticultural farmers, as well as the energy-sector.
He said winter was not expected to be influenced by El Nino.
‘‘It will be a fairly regular winter — probably on the drier side, and probably a little bit on the warmer side overall for Southland and Otago.
‘‘But that doesn’t mean that you won’t get cold outbreaks, low-level snow events, or frosty events.’’
As the regions moved into spring, Mr Trewinnard said the El Nino pattern would start to ‘‘couple up’’ with local weather systems.
‘‘El Nino is like a spice that you sprinkle on your meal — it adds a background flavour that takes the meal in a certain direction.
‘‘The character of the weather patterns will get enhanced by El Nino as we move through the spring.’’
He said spring was the time of year when westerly and southwesterly airflows were the most dominant weather pattern.
‘‘What that means for most of Otago, particularly the inland areas and inland Southland too, is relatively dry and quite windy conditions with the temperatures alternating quite a lot between warm northwest days and cooler southwest days.’’
However, along the south coast and the east coast, all the way up to Dunedin, it would be a significantly windier than usual spring, and there would be quite changeable showery conditions.
When summer arrived, wind speeds would start to drop, and the regions may start to get several days of showery weather and then several days of fine weather.
Inland Otago, north Otago, central Otago, and northern Southland areas that are more sheltered from the westerly and southwesterly wind flows, would also start to dry out, and drought could become a concern for farmers during the summer.
It was something southern farmers should be preparing for, he said.
‘‘We’ve seen enough El Nino events over the decades to know how they evolve and how they play out. So we can plan for them.
‘‘We can make strategic decisions around feed plans, supplementary feed — have you got enough if the grass stops growing because it gets a bit droughty; how will you cope in Southland if you have persistent periods of cold, showery weather?
‘‘You might also look at your stocking levels, your rotation plans across your paddocks and things like that.
‘‘And if you’re growing grapes or stone fruit in Central Otago, you’ve probably got to plan with these southwest changes coming through in the springtime, that it may be frostier than normal, and you may have more variable rainfall and need more irrigation through the summer period.
‘‘Operators who move early in El Nino years consistently come out in better shape than those who wait.’’
