Does El Nino impact temperature in Chennai?

Does El Nino impact temperature in Chennai? In our El Nino series which we started with our First Post studying about possible relationship between El Nino and temperatures today we try to find the answer to the question on how much does El Nino impact temperature in Chennai.

As mentioned in our first post we had undertaken the study with mean temperature data for the period 1950 to 2015 using the station data provided by NASA GISS. The scope of the study is to see possible influence of ENSO on temperature pattern for the months of January – May.  Those years that have seen an ONI Index of 0.5 (indicator of El Nino) during the December – February quarter have been assumed as El Nino Years. We had covered Mumbai & Bangalore in our first part while we will look at Chennai in detail today.


In the first part of the post we take a look at which of the years have seen the highest mean temperatures for the respective months.  As one can clearly observe except 2012 which was a La Nina year, the highest mean temperatures for Chennai has always been recorded during El Nino years.  Closer scrutiny also shows years like 1988, 1998, 2010 were devolving years while 1953 & 1954 which saw the highest mean temperature was a multi year El Nino.  All of these peak years have seen the temperature record about a couple of degrees  higher than the average temperature during the period of study.

Considering we have a devolving El Nino Year in 2016 a look at the current year’s mean temperature data for the first 2 months we can observe both of these months have seen the mean temperatures show an anomaly of about 2 degrees over the period of study.


The second part of the study we look at two aspects the highest temperature recorded ever and the difference in temperature pattern between El Nino & Non El Nino years.  As one can see if one looks at the highest temperature data only 2 out of the 5 months have seen the highest temperature recorded during an El Nino year indicating potentially local factors which have played a role in the spikes in temperature over a set of days.

But when one looks at the numbers splitting the El Nino and Non El Nino years the impact is quite clearly visible.  There is on an average El Nino years are about 0.5 degrees warmer than non El Nino years indicating a possibly strong relationship between El Nino and Chennai temperature.

Does El Nino impact temperature in Chennai? Yes. Of the 8 places that was studied Chennai possibly has the strongest relationship between rising temperatures & El Nino