Early October Comparative
El Niņo and La Niņa Climatology
(1997-1998 to 2017-2018)


 This climatology is designed as a quick reference to allow users to see patterns, or non-patterns, between "similar" ENSO (El Niņo Southern Oscillation) warm and cool Sea Surface Temperature (SST) events using the NASA JPL Sea Height Anomaly products. My initial takeaway is that by looking at the bigger picture and not just the equatorial Oceanic Niņo Index (ONI) data, may give us a better idea of the potential effects from one season over another in terms of winter precipitation.

For example, looking at the 1997-98 and 2015-16 very strong El Niņos, it is seen that the waters of the northeastern Pacific 1997 were extremely warm compated to 2015-16.  Was these a driving force between it being very wet for the former and not nearly so for the latter?

Or for last year's (2016-17) very wet weak La Niņa was the warmer than normal water between about 5 degrees N and 20 degrees N a factor in the wet year for California verus the 2008-09 dry weak La Niņa events that saw cool water in this same region.

But, like any similar climatology, the usual caveats apply that this is simply a record of past events and not intended to be a standalone forecast tool.

 Jan Null, CCM
Winter ENSO Type ASO ONI Max ONI Early October Pacific
Sea Ht Anomaly
Winter (Nov to Mar) Precipitation
2017-18  Weak La Niņa        
2016-17  Weak La Niņa  -0.7  -0.7    
2015-16  Very Strong El Niņo  +2.1  +2.6    
2014-15  Weak El Niņo  +0.2  +0.7    
2013-14  Neutral  -0.3  -0.4    
2012-13   Neutral  -0.3  -0.4  
2011-12  Moderate La Niņa  -0.9  -1.1    
2010-11  Strong La Niņa  -1.6  -1.7    
2009-10  Moderate El Niņo   +0.7  +1.6    
2008-09  Weak La Niņa  -0.3  -0.8    
2007-08  Strong La Niņa  -1.1  -1.6    
2006-07  Weak El Niņo  +0.5  +0.9    
2005-06  Weak La Niņa  -0.1  -0.8    
2004-05  Weak El Niņo  +0.7  +0.7  
2003-04   Neutral  +0.3  +0.4    
2002-03  Moderate El Niņo  +1.0  +1.3    
2001-02   Neutral  -0.2 -0.3   
2000-01  Weak La Niņa  -0.5  -0.7    
1999-00  Strong La Niņa  -1.2  -1.7    
1998-99  Strong La Niņa  -1.3  -1.6    
1997-98  Very Strong El Niņo  +2.1  +2.4