2020 Likely to be the Hottest Year in NASA's Records

With July data in, we are still predicting a ~70% of a new record for the GISTEMP annual mean. Odds are a little less should a medium to strong La Niña develop in the fall.

It is certain to be a top 5 yr & to be the 6th year in a row more than 1°C warmer than the late 19th C. pic.twitter.com/1Toz41SwFw

— Gavin Schmidt (@ClimateOfGavin) August 14, 2020

Here, in short, is how they calculate this: 

it's based on the historical relationship between YTD and the annual mean, plus a conditioning for what Nino34 might be doing at the end of the year.

— Gavin Schmidt (@ClimateOfGavin) August 14, 2020