Much of the UK media has been very persistent in the past few months in saying that large positive anomaly El Niño years herald cold winters – basing their assumption on one year: 2009/10.
Whilst that winter was very cold, among the top 10 coldest of the last 70 years in this area, another El Niño year, 1997/98 – the strongest in recent history – brought London its third-warmest winter in a record going back to 1797.
When I had a look at ENSO data going back to 1950 a few months ago I found it impossible to find a definitive teleconnection between El Niño and winters in north-west Europe. However, now that we are midway through November, and with a fair impression of how the monthly mean will finish, I had another look.
NOAA data shows that the most similar El Niño years to this are: 1957, 1965, 1972, 1982, 1997, 2002. Taking in to account only mean temperature shows that November values have increased.
What does this mean for this winter? It is still impossible to tell and is just another variable to consider when the time comes to predict winter.