I've been following this NINO for quite some time & especially the ONI and decided to perform some calculations using the same methodology as the CPC on a multitude of datasets. From what I've derived thus far, ERSSTv4 is the odd man out & a low outlier wrt estimating this El Nino's intensity, only surpassed in this department by the unadjusted IOCADSv2.5 dataset which is showing this NINO @ +1.38C for JAS (lol). In fact, the average of the datasets that I've looked at (ERSSTv3b, ERSSTv4, NCEP R1, Kaplan v2, OISSTv2, & CDAS 1) (HADSST3 & HADISST haven't updated yet but have been closely following the aforementioned datasets) & updated thru JAS is ~+1.75C. Here are the specific numbers.... NCEP R1: +1.84C, Kaplan's Extended SSTv2: +1.90C, OISSTv2 +1.90C, CDAS 1: +1.86C. Even though the latest ONI figure from ERSSTv4 is impressive (+1.46C), it's very likely to be way underdone & is a huge difference from the reanalysis, higher resolution, & SST reconstruction products that *directly* integrate satellite data into their fields unlike ERSST that relies on EOTs from OISSTv2. In fact, the only other dataset that I'm aware of that extends the full length of the observational record & updates in real-time, (Kaplan's Extended SSTv2) with an ONI value coming in @ +1.90C is the 2nd highest on record for JAS since 1870 (only behind 1877-78 (+1.96)) & is a far cry from ERSSTv4 which places this NINO in 6th place at the moment (behind 1877, 1997, 1902, 1905, & 1987). While ERSSTv4's latest ONI value is impressive, Kaplan's is historic & practically unprecedented since the mid 19th century...