Honestly I will say that I have not checked that specific map very often. It's not of particular interest, day to day, for me.
It seemed like some individual days in the 2016 El Nino were very high like +0.8C or something. For example, Feb 2016 is listed as +0.817C on that web site. The recently monthly anomaly values, like July and August 2026, are high (on that web site), +0.764C and +0.942C. So that's pretty insane.