Climate bulletin - January 2017
Summary of the world's climate system in January 2017
The global average temperature for January 2017 as estimated from the HadCRUT4 data set was 0.74±0.16°C above the 1961-1990 average. Globally January 2017 was one of the six warmest Januarys on record. Global temperature data sets maintained by NASA GISS and NOAA NCEI also show that January was a very warm month globally. Sea-surface temperatures in the tropical Pacific were near or below average indicating neutral ENSO conditions.
The global average land temperature for January 2017 was 1.33 ± 0.38°C above the 1961-1990 average. For global land areas January 2017 was one of the 16 warmest Januarys on record. Unusual warmth – temperatures exceeding the 90th percentile for the month – affected eastern areas of north America, Mexico, eastern Australia, parts of Brazil and southern South America, southeast Asia and tropical areas of Africa including Madagascar. Unusual cold – temperatures below the 10th percentile for the month – was recorded in parts of southeast Europe, and limited areas of western north America, northern Australia and New Zealand.
The global average sea-surface temperature for January 2017 was 0.49 ± 0.08°C above the 1961-1990 average, nominally the second warmest on record and certainly one of the 12 warmest. Sea surface temperatures in the tropical Pacific were near or below average, indicating neutral ENSO conditions. Unusually-warm waters were recorded across much of the North Atlantic, the western rim of the tropical Pacific and around 20°S and 30°N in the central Pacific. The Arabian Sea and limited areas of the south Atlantic and Indian Ocean around 30°S were also unusually warm. Unusually cold waters were observed in the southeast Indian Ocean, the north Pacific around 45°N and in parts of the southern Ocean.
Higher than average precipitation totals (based on the monthly first-guess analysis by the Global Precipitation Climatology Centre (GPCC) were recorded across much of the USA, particularly California, Ecuador, Peru and northern Brazil, as well as southern parts of both Australia and New Zealand. Under the influence of persistent anticyclonic conditions, large areas of Europe were drier and colder than average (France had its driest January in a series beginning in 1959), with the Mediterranean and the western edge of Norway being the wetter-than-average exceptions.
According to data from the National Snow and Ice Data Center in the US, Northern hemisphere (Arctic) sea ice extent was 13.38 million square kilometres. January 2017 was nominally the least extensive January ice on record. From 21st October to the end of January 2017 only 12 days did not set new daily records for low Arctic sea-ice extent. Southern hemisphere (Antarctic) sea ice extent was 4.04 million square kilometres. January 2017 was nominally the least extensive January on record here.