Last month was a scorcher for global temperatures with warmth over land and sea breaking records for June while sea-surface temperatures posted their largest departure from long-term averages for any month.
Combined average temperatures over land and sea were 0.72 degrees above the 20th century average of 15.5 degrees, making it the hottest June and adding to the record May and equal record April, according to the US National Oceanic and Atmospheric Administration (NOAA).
More striking for climatologists, though, were the sea-surface temperatures. These came in 0.64 degrees above the 20th century average of 16.4 degrees – the first time any month had exceeded the long-run norm by more than 0.6 degrees.
Parts of all major ocean basins notched their warmest June, with almost all the Indian Ocean and regions off south-eastern Australia the hottest on record.
An El Nino event remains about a 70 per cent chance of forming during the northern summer, which could see more records tumble. The weather pattern sees the central and eastern equatorial Pacific Ocean becoming relatively warm compared with western regions, and typically brings hotter, drier than usual conditions to south-east Asia and Australia.
Australia posted its hottest 12 months on record in the year to June, while 2013 was the hottest calendar year in more than a century of records, according to the Bureau of Meteorology.
While June was another month of above-average temperatures, Western Australia and the Northern Territory were cooler than normal – breaking a sequence begun in February in which every state or territory had above-average warmth, NOAA noted.
June was the 352nd month when global temperatures were above the 20th century average – with the last below-average month in February 1985 when Bob Hawke was in his first term as Prime Minister and Ronald Reagan in his second-term in the White House.
Minor cool snap
Apart from a cool snap over the past few days, cities such as Sydney and Melbourne are continuing their run of above-average conditions with temperatures likely to again edge up over the coming week.
So far this year, above-average maximums in Sydney are running at about 2.5-to-one compared with cooler-than-usual weather, according to the Bureau of Meteorology.
In the first half of the year, Sydney had 162 days of 20 degrees or warmer conditions, easily ahead of the previous record in 2004 of 157.
After tops of 18 on Tuesday and Wednesday, Sydney can expect 20-21 degree days out to next Monday, with little more than the odd shower over the period. Maximums for the city are running about 2 degrees above the July average of 16.3 degrees so far this month.
Melbourne’s maximums in July have been closer to the long-run average of 13.5 degrees. Aside from a top of 14 degrees forecast for Tuesday and again on Friday, other days should be in the 15-17 range, according to the bureau.
Climate scientists say man-made emissions of greenhouse gases are trapping more solar heat and leading to the global warming that increasing the likelihood that hot rather than cold records will be broken.
The first half of the year tied 2002 as the third-warmest on record for land and sea-surface temperatures, NOAA said.
