Climate bulletin - March 2017
Summary of the world's climate system in March 2017
The global average temperature for March 2017 as estimated from the HadCRUT4 data set was 0.88±0.14°C above the 1961-1990 average. Globally March 2017 was one of the four warmest months of March on record and most likely second warmest. Global temperature data sets maintained by NASA GISS and NOAA NCEI also show that March was a very warm month globally. Sea-surface temperatures in much of the tropical Pacific were near or above average indicating neutral ENSO conditions. However, SSTs in the eastern Tropical Pacific, close to the coast of South America, were warmer than average.
The global average land temperature for March 2017 was 1.51 ± 0.26°C above the 1961-1990 average. For global land areas March 2017 was nominally the second warmest March on record and very likely in the top five, though not the warmest. Unusual warmth – temperatures exceeding the 90th percentile for the month – was recorded in the western USA (Colorado and New Mexico were record warm), parts of Brazil, West Africa, South Africa, Madagascar, eastern Australia, parts of southern Asia and in a band running from central and southern Europe across the north of Eurasia where monthly average temperature exceeded 10°C above average across a large area. A number of countries (the Russian Federation, France, Germany and Austria each had their warmest March on record, Netherland, Serbia and Switzerland their second warmest). The temperature pattern across Eurasia and North America is consistent with the positive phase of the Arctic Oscillation. Unusual cold – temperatures below the 10th percentile for the month – affected parts of western and eastern Canada, Bangladesh and a few other limited areas: south of Lake Balgash, western Colombia, and the Falkland Islands (note that SSTs in the region of the Falkands were higher than average).
The global average sea-surface temperature for March 2017 was 0.55 ± 0.08°C above the 1961-1990 average, nominally the second warmest on record and very likely between second and fifth warmest. Sea surface temperatures in the tropical Pacific were near average with some areas warmer than the long-term mean, indicating neutral ENSO conditions. However, in the east, near the coast of South America anomalies locally exceeded 4°C. Unusually-warm waters were recorded across large areas of the North Atlantic, tropical Atlantic, the western Indian Ocean, western Pacific and around 30°S and 30°N in the Pacific Ocean. Unusually cold waters were observed in the eastern Indian Ocean. Other notable areas of colder-than-average SST were an area south of Greenland which has been colder than average for the past few years and an area in the South Atlantic which has been cooler than average since late 2015.
Higher than average precipitation totals (based on the monthly first-guess analysis by Global Precipitation Climatology Centre, GPCC) were recorded across western parts of the US, areas of South America (including Venezuela, Colombia, Ecuador, Chile and parts of Argentina), Bangladesh, parts of China and Mongolia, and New Zealand’s North Island. Tropical cyclone Enawo, which reached category 4, brought above average rainfall to Madagascar. Unusually high rainfall totals (in the top 10% of the historical record) were recorded along the east coast of Australia largely associated with severe tropical cyclone Debbie. Tropical Cyclone Blanche brought heavy rain to parts of Western Australia early in the month. In contrast, parts of South Australia recorded rainfall totals in the lowest 10%. Other areas of drier-than-average conditions included: parts of South Africa, the southeast US, Italy and some areas of east Africa where there have been longer term rainfall deficits.
Based on data from the HadISST.18.104.22.168 data set, both Northern hemisphere (Arctic) and Southern Hemisphere (Antarctic) sea ice extent were nominally the least extensive March sea ice on record for the respective hemispheres. This analysis is consistent with data from the National Snow and Ice Data Center in the US. Sea-ice extent has been unusually low in both hemispheres since the late 2016. March saw the lowest recorded daily sea ice extent for March in both hemispheres within the same week. For more details and analysis of the winter ice-extents, see the sea-ice monitoring brief.