Sunday, March 14, 2021

GISS February global down by 0.17°C from January.

The GISS V4 land/ocean temperature anomaly was 0.67°C in February 2021, down from 0.84°C in January. This matched the 0.2°C reduction reported for TempLS, although with further data that has shrunk to a 0.143C fall. Jim Hansen notes that it was historically cool, although the four Februarys in 2011-2014 were cooler.

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. That cold wedge stretching from Alaska to the middle of the USA struck deep into the heart of Texas with some of the coldest weather I've seen here since the 1980's. Not only was it cold, but temperatures stayed below freezing for 5 to 6 days in a row here in Central Texas, which is a new record. And the cold started with an ice storm, followed by the heaviest snowfall for February (with records back to 1898 and 4th heaviest for any month), followed by yet more ice on top of the snow. Power was out at our house for 37 hours, right at the time of the coldest temperatures. Many homes here have water lines running through the attic, as does ours. Thankfully no broken water lines at our house, but many were not so lucky. With the power outage, my home weather station indoor console was not able to record data from the outside sensor array, so I didn't get to measure the lowest temperatures in our backyard. But a few home weather stations in the Austin metro area measured temperatures a little below 0F and I suspect it was close to 0F at our house, since it usually ranks among about the 10-20 percent of coldest weather stations in the area.

  2. I update my prediction for GISS temperature anomaly using data up to Feb21. I'm using the new version that uses MEI2 values.
    MAM21 0.90+-0.15
    JJA21 0.91+-0.10
    SON21 1.03+-0.13
    J-D21 0.94+-0.08
    DJF22 0.94+-0.26
    Now it gives a 1% chance of breaking the 2020 record again in 2021.