Global climate trend since Dec. 1 1978: +0.13 C per decade

January Temperatures (preliminary)

Global composite temp.: +0.37 C (+0.67 °F) above seasonal average

Northern Hemisphere.: +0.32 C (+0.58 °F) above seasonal average

Southern Hemisphere.: +0.42 C (+0.76 °F) above seasonal average

Tropics.: +0.37 C (+0.67 °F) above seasonal average

December Temperatures (final) Global composite temp.: +0.25 C (+0.45 °F) above seasonal average

Northern Hemisphere.: +0.32 C (+0.58 °F) above seasonal average

Southern Hemisphere.: +0.19 C (+0.34 °F) above seasonal average

Tropics.: +0.32 C (+0.58 °F) above seasonal average

Notes on data released February 1, 2019 (v6.0)

Newswise — The global average bulk-layer atmospheric temperature anomaly rose by +0.12 °C (0.22 °F) in January to +0.37°C (+0.67°F) led by a warming in the SH oceanic areas of 0.31°C (0.56 °F) over last month. Once again we mention that indications remain that a warm El Niño will become fully developed in the tropical Pacific Ocean. However, the magnitude of the indicators is still not strong enough to cross the threshold of the formal definition of El Niño. If it does occur, it is likely to be a modest event.

The month’s coldest seasonally-adjusted temperature departure from average was located over the Ionian Sea (-2.7 °C, -4.9 °F) and the warmest over the North Atlantic southeast of Greenland (+3.2 °C, +5.8 °F).

The monthly map for January 2019 shows the usual situation of alternating hot and cold regions in the subtropical and higher latitudes. This time, the cold regions are found in eastern Canada, Europe (from the Barents Sea southward to the Mediterranean Sea), India, western Pacific Ocean and broad regions around Antarctica northward. The warm spots are roughly in between these, landing in western North America, the North Atlantic Ocean, the Middle East, Eastern China, and several areas over the Pacific and South Atlantic oceans with a particularly significant hot spot over southeastern Australia (summertime) for the second month in a row.

Spoiler Alert (Repeated until accomplished – no estimate yet): Well, the time is once again approaching when new changes are required for the currently operating satellites as their performance changes with age. NOAA-18 has been operating for 13 years and is now past its time frame for accurate diurnal adjustments based on initial drifting, meaning the adjustments are adding spurious warming to the time series. On the other hand, NOAA-19 has also drifted so far that it too is introducing an error, but given its direction of drift, these errors are of the opposite sign. The two satellites are almost compensating for each other, but not to our satisfaction. In addition, the current non-drifting satellite operated by the Europeans, MetOP-B, has not yet been adjusted or “neutralized” for it’s seasonal peculiarities related to the diurnal cycle. While these MetOP-B peculiarities do not affect the long-term global trend, they do introduce error within a particular year in specific locations over land. So, all in all, we anticipate generating new adjustments for NOAA-18 and NOAA-19 to account for their behavior of late and shall also modify MetOP-B to account for it’s unique seasonal cycle. This will be part of a coordinated plan to eventually merge NOAA’s new microwave sensor (ATMS) carried on Suomi NPP and the new NOAA series JPSS. We are hoping that NOAA-19 will be the last spacecraft for which drifting adjustments will be required as the newer satellites (MetOP, NPP, JPSS) have on-board propulsion to keep them in stable orbits. With so many new items to test and then incorporate, we are waiting until we are confident that these adjustments/additions are appropriately stable before moving to the next version. In the meantime, we shall continue to produce v6.0.

As part of an ongoing joint project between UAH, NOAA and NASA, Christy and Dr. Roy Spencer, an ESSC principal scientist, use data gathered by advanced microwave sounding units on NOAA, NASA and European satellites to get accurate temperature readings for almost all regions of the Earth. This includes remote desert, ocean and rain forest areas where reliable climate data are not otherwise available.

The satellite-based instruments measure the temperature of the atmosphere from the surface up to an altitude of about eight kilometers above sea level. Once the monthly temperature data are collected and processed, they are placed in a "public" computer file for immediate access by atmospheric scientists in the U.S. and abroad.

The complete version 6 lower troposphere dataset is available here: Archived color maps of local temperature anomalies are available on-line at:

Neither Christy nor Spencer receives any research support or funding from oil, coal or industrial companies or organizations, or from any private or special interest groups. All of their climate research funding comes from federal and state grants or contracts.

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