Tuesday, June 15, 2021

GISS May global temperature up by 0.04°C from April.

The GISS V4 land/ocean temperature anomaly was 0.80°C in May 2021, up from 0.76°C in April. This small rise is similar to the 0.012°C increase reported for TempLS. Jim Hansen's report is here.

As usual here, I will compare the GISS and earlier TempLS plots below the jump.

Here is GISS V4

And here is the TempLS V4 LOESS-based plot

This post is part of a series that has now run for seven years. The GISS data completes the month cycle, and is compared with the TempLS result and map. GISS lists its reports here, and I post the monthly averages here.

The TempLS mesh data is reported here, and the recent history of monthly readings is here. Unadjusted GHCN is normally used, but if you click the TempLS button there, it will show data with adjusted, and also with different integration methods. There is an interactive graph using 1981-2010 base period here which you can use to show different periods, or compare with other indices. There is a general guide to TempLS here.

The reporting cycle starts with a report of the daily reanalysis index on about the 4th of the month. The next post is this, the TempLS report, usually about the 8th. Then when the GISS result comes out, usually about the 15th, I discuss it and compare with TempLS. The TempLS graph uses a spherical harmonics to the TempLS mesh residuals; the residuals are displayed more directly using a triangular grid in a better resolved WebGL plot here.

A list of earlier monthly reports of each series in date order is here:

  1. NCEP/NCAR Reanalysis report
  2. TempLS report
  3. GISS report and comparison with TempLS


  1. The annual GISS Temp has a remarkably strong correlation with the Jan.-May average. Also the June-value should be beween the values of Jan/Feb. 21. This points to an estimate of the Jan-Dec. value of 0.74 in GISS Loti mean, which is more than 0.3K below 2020. Any thoughts?

    1. Frank,
      Based on NCEP/NCAR, it seems that June will be as cold as February, and yes, it does look like being a cool year. I guess Jan-May has a big influence because those months are the most influenced by ENSO.
      In TempLS, 2021 so far is at 0.645°C. If that is where it ends up, it will be the coolest since 2014 (0.588°C). However, 2014 was, in its day, the record warm year. 2021 has some chance of passing 2018 (0.688°C).

    2. Good comment regarding placing the presumed 2021 annual temperature. On the other hand, the so-called "pause" is often refrred to as beeing betweein 2002 and 2012, and for instance HADCRUT4 reported annual 2002 anomaly to 0.496, in 2012; 0.470 and in 2014 as 0.579, and 2018 as 0.597. Hence, the record high temp anomalyin 2014 was long overdue.
      If 2021 ends around 2018, it will end up being only 0.1 C above the anomaly 19 years ago, but a more reasonable comparison is of course the 2001, also being a Nina year. Still, 2001 with 0.441 is only about 0.15 C cooler, demonstrating that 2021 might end up considerably lower than expected from a presumed increas of 0.2/decade.

    3. Well, 2001 at .441°C was not cool for its time; 1999 and 2000 were both about 0.26°C.

    4. Thank you for recalling the data 20 years ago. This is very important for analyzing the climatic situation.

  2. I update my prediction for GISS temperature anomaly using data up to May21. I'm using the new version that uses MEI2 values.
    JJA21 0.90+-0.09
    SON21 1.00+-0.12
    J-D21 0.89+-0.05
    DJF22 0.87+-0.20
    MAM22 0.98+-0.17
    Now it gives no chance of breaking the 2020 record again in 2021.