During an El Niño sea surface temperature in the East Pacific warms, altering weather patterns around the globe. However, because of the UK distance from the ‘main event’, the influence of an El Niño tends to be weaker and less predictable than elsewhere.
There is a link in late winter, when there’s a slightly higher risk of a colder than usual end to winter in El Niño years.
But that’s not the end of the influences on the UK winter.
Other factors like sea surface temperature in the North Atlantic, the Sun’s output, and changes in winds high in the atmosphere above the Equator, known as the Quasi-Biennial Oscillation, play their part.
These could wipe out the influence from El Niño, and all of them need to be taken into account to predict the winter.
NOAA in the US says there’s a 95% chance that El Niño will continue through this coming Northern Hemisphere winter, gradually weakening through spring 2016, and that this El Nino is “pretty strong”.
It was a very warm winter in much of South America; in some areas, it was the warmest since records began in 1948.
Parts of Argentina, Uruguay, and Chile had a lot of rain during July and August but Central America and the Caribbean are very dry, with the lack of rain in June-August adding to a severe drought throughout the region. However, El Niño impacts are of course not guaranteed. Australia’s recent winter was not nearly as dry as it has been during past El Niños.
Last year, scientists looking at the impacts of ‘El Niño’ and ‘La Nina’ on agricultural production, found that El Niño events were likely to improve the global mean soybean yield by 2.1 to 5.4%, but the effect on maize, rice and wheat was more variable, with changes in yield ranging from a 4.3 reduction to a small increase of 0.8.
You can see the Met Office’s three-monthly outlook here.