December 2023 Monthly Global Climate Report

December 2023 Global Climate Report | National Centers for Environmental Information (NCEI)

Temperature

Coinciding with the release of the January 2023 Global Climate Report, the NOAA Global Surface Temperature (NOAAGlobalTemp) dataset version 5.1.0 replaced version 5.0.0. This new version includes complete global coverage and an extension of the data record back in time an additional 30 years to January 1850. While anomalies and ranks might differ slightly from what was reported previously, the main conclusions regarding global climate change are very similar to the previous version. Please see our Commonly Asked Questions Document and web story for additional information.

NOAA's National Centers for Environmental Information calculates the global temperature anomaly every month based on preliminary data generated from authoritative datasets of temperature observations from around the globe. The major dataset, NOAAGlobalTemp version 5.1.0, updated in 2023, uses comprehensive data collections of increased global area coverage over both land and ocean surfaces. NOAAGlobalTempv5.1.0 is a reconstructed dataset, meaning that the entire period of record is recalculated each month with new data. Based on those new calculations, the new historical data can bring about updates to previously reported values. These factors, together, mean that calculations from the past may be superseded by the most recent data and can affect the numbers reported in the monthly climate reports. The most current reconstruction analysis is always considered the most representative and precise of the climate system, and it is publicly available through Climate at a Glance.

December 2023

The Decmeber global surface temperature was 1.43°C (2.57°F) above the 20th-century average of 12.2°C (54.0°F), making it the warmest December on record. This was 0.30&degC (0.54°F) above the previous record from December 2015. December 2023 marked the 48th-consecutive December and the 538th-consecutive month with temperatures at least nominally above the 20th-century average.

December saw a record-high monthly global ocean surface temperature for the ninth consecutive month. El Niño conditions that emerged in June continued into December, and according to NOAA's Climate Prediction Center it is likely that El Niño will continue for the next several months with a 73% chance that ENSO-neutral conditions will emerge during April–June 2024.

The Northern Hemisphere had its warmest December on record by a wide margin at 1.98°C (3.56°F) above average. This surpassed the previous record set in 2022 by 0.82°C (1.48°F). Both land and ocean temperatures were at record-highs for the Northern Hemisphere this December. The Arctic region had its second-warmest December on record.

December 2023 in the Southern Hemisphere also ranked warmest on record at 0.88°C (1.58°F) above average. While the average ocean-only temperature for December in the Southern Hemisphere ranked highest on record this December, land-only temperature was fourth warmest on record. Meanwhile, the Antarctic region had its 48th-warmest December.

A smoothed map of blended land and sea surface temperature anomalies is also available.

Temperatures were above average throughout most of North America, the Arctic, the northern half of South America, Africa, central and southern Europe, southwestern and southeastern Asia, and Australia. Parts of north-central North America, northern and central South America, the Middle East, and eastern and southern Asia experienced record-warm temperatures this month. Sea surface temperatures were above average across much of the northern, western, and equatorial Pacific Ocean as well as parts of the western Indian Oceans. Much of the central Atlantic Ocean was record warm for the month. Record-warm temperatures covered approximately 13.5% of the world's surface this December, which was the highest percentage for December since the start of records in 1951 and more than double the previous record of 6.6% in 2015.

Temperatures were near to cooler than average from northern Europe to eastern Asia, and across parts of Antarctica. Sea surface temperatures were near to below average over parts of the southeastern Pacific Ocean, the Southern Ocean, and the northern Atlantic Ocean. Less than 1% of the world's surface had a record-cold December.

North America and South America both had their warmest December on record.

The contiguous U.S. had its fifth-warmest December in the 129-year record.
- The Caribbean Islands region had its warmest December on record.

December 2023 ranked second warmest on record for Africa and the Arctic while Oceania ranked third warmest, Australia fourth warmest, and Europe seventh warmest on record. Asia had its 18th-warmest December on record and was the warmest December since 2019.

| December | Anomaly | | Rank(out of 174 years) | |
| °C | °F | Year(s) | | |
| Global | | | | |

Ocean Land and Ocean Land Ocean Land and Ocean Land Ocean Land and Ocean

500 mb maps

In the atmosphere, 500-millibar height pressure anomalies correlate well with temperatures at the Earth's surface. The average position of the upper-level ridges of high pressure and troughs of low pressure—depicted by positive and negative 500-millibar height anomalies on the map—is generally reflected by areas of positive and negative temperature anomalies at the surface, respectively.

Year-to-date Temperature: January–December 2023

The January–December global surface temperature ranked highest in the 174-year record at 1.18°C (2.12°F) above the 1901–2000 average of 13.9°C (57.0°F). This surpassed the previous record from January–December 2016 by 0.13°C (0.23°F). According to NCEI's statistical analysis and data through December, there is a one-in-three chance that 2024 will be warmer than 2023 and a 99 percent chance that 2024 will rank among the five warmest years on record.

January–November in the Northern Hemisphere ranked warmest on record at 1.54°C (2.77°F) above average. Both the ocean-only and land-only temperatures also ranked highest on record for the Northern Hemisphere during 2023. January–December in the Southern Hemisphere also ranked warmest on record at 0.82°C (1.48°F) above average.

North America, South America, and Africa had their warmest year on record, while it was the second-warmest year on record for Europe and Asia. January–December 2023 ranked 10th warmest on record for Oceania.

A smoothed map of blended land and sea surface temperature anomalies is also available.

The year was characterized by near-record warm temperatures across much of the globe, with record-high annual temperatures across parts of Canada, the southern U.S., Central America, South America, Africa, Europe, Asia, and a large portion of the central and north-eastern Atlantic as well as portions of the South Atlantic, Indian and South Pacific oceans. Meanwhile, cooler-than-average temperatures were limited to portions of the Southern Ocean and Antarctica.

| January–December | Anomaly | Rank(out of 174 years) | Records | |
| | °C | °F | Year(s) | °C |
| Global | | | | |

Ocean Land and Ocean Land Ocean Land and Ocean Land Ocean Land and Ocean

Precipitation

The maps shown below represent land-only precipitation anomalies (left, using a base period of 1961–1990) and land-only percent of normal precipitation (right, using the period of record) based on the GHCN dataset of land surface stations.

December 2023

Significantly below-average December precipitation occurred from the Southwest to the northern Plains and from the Gulf Coast to the Great Lakes in the U.S., eastern Brazil, the Mediterranean, parts of southwestern Asia, Southeast Asia and Australia. Above-average precipitation occurred from the southern Plains to the Upper Midwest and along the U.S. East Coast, Argentina, and from central Europe to east-central Asia.

Global Precipitation Climatology Project (GPCP)

The following analysis is based upon the Global Precipitation Climatology Project (GPCP) Interim Climate Data Record. It is provided courtesy of the GPCP Principal Investigator team at the University of Maryland.

December Highlights:

- The current El Niño continues to dominate the tropical rainfall anomaly patterns over ocean and land with generally dry conditions over Australia and the Amazon region.
- The southern U.S. and Mexico have a mixed pattern of wet and dry, unlike what is expected under El Nino conditions, i.e., a precipitation surplus.
- Much of Europe continues with above average precipitation to further relieve drought conditions, although Spain and Portugal and most of the Mediterranean were dry.
- Intensity of global ITCZ sets record high for December, indicating impacts of global warming and El Niño on intensity of tropical rainfall.

The mean precipitation map for this December (see Fig. 1, top panel) shows a intense Pacific ITCZ and SPCZ as the strong focus for this month. The ITCZ extends east and west from there with overland features in Africa and South America broader and further south than the over ocean segments. The tilted storm tracks of the Northern Hemisphere are evident over the midlatitude oceans impinging on the northwest coasts of North America and Europe. In the southern oceans weaker tilted features are evident associated with the continents there, along with the narrow ring of higher precipitation circling the globe at about 55-60°S this month.

The 2023 year has been noted as a record warm year, and its December was also the warmest December. The current El Niño contributes to the warm surface temperatures (in addition to the general global warming contributions). The anomaly maps for December (Fig. 1, middle and bottom panels) reflect these forcings, especially those from the El Niño in the tropics. Over the tropical central Pacific a dramatic, intense, narrow and positive rainfall anomaly exists along the ITCZ and into the Southern Hemisphere in the SPCZ. This feature is a final result of the SST positive anomaly in this general area creating above average evaporation, additional atmospheric moisture, convection and rain as part of the upward branch of the Walker circulation. To the west a large, broad mostly negative anomaly is centered over Indonesia associated with the shifted position of the downward branch of the Walker circulation. As seen in Fig. 2 the El Niño composite for the month of December (from previous Decembers with El Niño present) has a similar pattern over these regions (repeated in the figure for easy comparison). To the north of the central Pacific ITCZ there is a broad area of rainfall deficit, including the Hawaiian Islands in both the composite and this month’s analysis.

The influence of the this 2023 and continuing El Niño still holds in December over much of the tropics with the positive rainfall anomaly over the western Indian Ocean and the deficit over much of Australia and South America, where the relative lack of rainfall will extend the drought over much of the Amazon region. The Indian Ocean large-scale rainfall surplus feature contained a local high rainfall and flooding event in the Seychelles Islands and a short-lived Tropical Cyclone Michaung hitting eastern India with heavy rainfall, both early in the month. Over Africa the anomaly pattern is not exactly the same as in the composite, with the Horn of Africa being dry this month, different than the composite. However, floods and landslides plagued Kenya and Tanzania with over 300 dead, typical of El Niño conditions. Although most of Australia was drier than normal, the far northeast (e.g., Cairns and vicinity) was hit with remnants of TC Jasper, with up to 870 mm of rain, causing major floods in the region, an opposite extreme from what is expected during El Niño conditions. Over South America dryness as expected over the northern half of the continent, except for the northwest, but a rainfall surfeit reigns further south, e.g., Argentina, as expected from the El Niño composite. However, this month’s pattern over the Atlantic ITCZ bears little resemblance to the composite. The overall correlation between this December’s anomalies and the El Niño composite is +0.59, significantly higher than previous months’ values.

From the El Niño December composite in Fig. 2 one would expect this December to have a positive precipitation anomaly across much of the southern U.S. However, as was the case last month, the actual pattern was mixed dry and wet anomalies, although the east coast of the U.S. was wet, with relief from the weak drought in the middle Atlantic states and even some flooding along the east coast, including in Florida and Maine. There was also a positive anomaly in the northwest U.S., opposite of the El Niño usual pattern, and an episode of flooding in southern California, both linked to cyclone-related features with Atmospheric Rivers (AR). However, most of the southern U.S. is still waiting for its expected El Niño precipitation maximum, including increased snowpack in the southern Rockies, which is only at about 70% of normal for this point in the year.

Figure 3. (a) Time series of precipitation anomalies in December during 1979–2023. within two latitude bands over land and ocean: 0–10°N and 30–40°N. (b) The difference between the two bands.

Figure 3. (a) Time series of precipitation anomalies in December during 1979–2023. within two latitude bands over land and ocean: 0–10°N and 30–40°N. (b) The difference between the two bands.

Over Europe a positive precipitation anomaly this month extends from the Atlantic, across the UK, France and Germany and far into central Asia, with a notable heavy snowfall event in Germany. An alternative precipitation deficit feature runs from the Iberian peninsula eastward over most of the Mediterranean and bordering land areas to the north and south.

Background discussion of long-term means, variations and trends of global precipitation can be found in Adler et al. (2017), and with comparison with climate models in Gu and Adler (2022). The Global Precipitation Climatology Project (GPCP) monthly data set is a long-term (1979-present) analysis (Adler et al., 2018) using a combination of satellite and gauge information. An interim GPCP analysis completed within ~10 days of the end of the month allows the use of the GPCP analysis in climate monitoring and for this discussion.

Ocean Heat Content

Ocean Heat Content (OHC) is essential for understanding and modeling global climate since > 90% of excess heat in the Earth's system is absorbed by the ocean. Further, expansion due to increased ocean heat contributes to sea level rise. Change in OHC is calculated from the difference of observed temperature profiles from the long-term mean.

| Basin | 0-700 meters | Rank (1955-2023) | | | | | |
| | Entire Basin | | Northern Hemisphere | Southern Hemisphere | | |
| Atlantic | 8.576 | 2nd | 5.053 | 1st | 3.522 | 4th |
| Indian | 5.933 | 1st | 0.680 | 7th | 5.253 | 1st |
| Pacific | 7.557 | 1st | 3.666 | 1st | 3.890 | 3rd |
| World | 22.065 | 1st | 9.399 | 1st | 12.666 | 1st |
| Source: | | | | | | |

Global OHC for October-December 2023 is the highest October-December OHC, as well as the highest quarterly OHC, in our records, which extend back to 1955. In fact, 2023 was the warmest year on record for the World Ocean. Overall, the latest quarterly OHC reveals widespread warmer than normal conditions relative to the 1955-2006 mean, a situation observed since the end of 2016. The October-December 2023 OHC shows large scale features similar to those observed since early 2023, but a notable difference is observed in the tropical Pacific Ocean: while there is a meridional expansion of the higher than normal conditions associated with the 2023 El Niño, > 10x105 J/m3, which extend from the coast of South America to about 170°W, OHC is lower, < -10x105 J/m3, in the tropical western Pacific Ocean. Much higher, > 30x105 J/m3, than normal OHC conditions continue to exist at mid-latitudes in the central and western North Pacific Ocean, as well as in the Gulf of Mexico and Caribbean Sea, the Gulf Stream/North Atlantic Current, and the northern Antarctic Circumpolar Current in the Indian Ocean sector. Higher, > 10x105 J/m3, than normal OHC conditions dominate the western South Pacific Ocean, the Tasman Sea, and most of the South Atlantic Ocean. Cool conditions, < -10x105 J/m3, appear in the western subtropical North Pacific Ocean and in the subpolar North Atlantic Ocean south of Greenland. Higher, > 10x105 J/m3, than normal conditions now dominate most of the Indian Ocean, with the exception of the eastern tropics.Global OHC for October-December 2023 is the highest October-December OHC, as well as the highest quarterly OHC, in our records, which extend back to 1955. In fact, 2023 was the warmest year on record for the World Ocean. Overall, the latest quarterly OHC reveals widespread warmer than normal conditions relative to the 1955-2006 mean, a situation observed since the end of 2016. The October-December 2023 OHC shows large scale features similar to those observed since early 2023, but a notable difference is observed in the tropical Pacific Ocean: while there is a meridional expansion of the higher than normal conditions associated with the 2023 El Niño, > 10x105 J/m3, which extend from the coast of South America to about 170W, OHC is lower, < -10x105 J/m3, in the tropical western Pacific Ocean. Much higher, > 30x105 J/m3, than normal OHC conditions continue to exist at mid-latitudes in the central and western North Pacific Ocean, as well as in the Gulf of Mexico and Caribbean Sea, the Gulf Stream/North Atlantic Current, and the northern Antarctic Circumpolar Current in the Indian Ocean sector. Higher, > 10x105 J/m3, than normal OHC conditions dominate the western South Pacific Ocean, the Tasman Sea, and most of the South Atlantic Ocean. Cool conditions, < -10x105 J/m3, appear in the western subtropical North Pacific Ocean and in the subpolar North Atlantic Ocean south of Greenland. Higher, < 10x105 J/m3, than normal conditions now dominate most of the Indian Ocean, with the exception of the eastern tropics.

- Adler, R., G. Gu, M. Sapiano, J. Wang, G. Huffman 2017. Global Precipitation: Means, Variations and Trends During the Satellite Era (1979-2014). Surveys in Geophysics 38: 679-699, doi:10.1007/s10712-017-9416-4
- Adler, R., M. Sapiano, G. Huffman, J. Wang, G. Gu, D. Bolvin, L. Chiu, U. Schneider, A. Becker, E. Nelkin, P. Xie, R. Ferraro, D. Shin, 2018. The Global Precipitation Climatology Project (GPCP) Monthly Analysis (New Version 2.3) and a Review of 2017 Global Precipitation. Atmosphere. 9(4), 138; doi:10.3390/atmos9040138
- Gu, G., and R. Adler, 2022. Observed Variability and Trends in Global Precipitation During 1979-2020. Climate Dynamics, doi:10.1007/s00382-022-06567-9
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Citing This Report NOAA National Centers for Environmental Information, Monthly Global Climate Report for December 2023, published online January 2024, retrieved on January 13, 2024 from

https://www.ncei.noaa.gov/ access/ monitoring/ monthly-report/ global/ 202312.