Worldwide temperatures last month soared to new heights for   October, boosted by the second-strongest El Nino on record, adding to the likelihood that 2015 will also smash annual heat records. 
The amount of heat required to warm up just the top two metres of the El Nino hot spot in the Pacific has been calculated at 100 quadrillion kilojoules - or about the total annual energy use in the US.
Average global surface temperatures were 0.53 degrees above the 1981-2010 average and the warmest since reliable data began in 1891, figures from Japan Meteorological Agency show.
The departure from the long-term averages for   October easily eclipsed the 0.34 degree anomaly set only a year earlier, the agency said.
Scientists say El Ninos add 0.1 to 0.2 degrees to global temperatures. This boost is coming on top of background warming of about 0.9 degrees over the past century, increasing the likelihood that heat records will continue to fall.
The Japanese record reading is likely to be matched by other agencies in coming days. It suggests 2015 - already the warmest by far for the first nine months - will easily top 2014 as the hottest year since reliable data has been collected.
  October was hot in many parts of the world. In Australia the national reading was the most abnormally warm period for any month monitored since the Bureau of Meteorology was formed in 1910.
Maximum temperatures averaged 3.44 degrees above the long-run average, the bureau said. Almost all of southern Australia recorded its hottest   October, driven higher by a big heatwave across the region.
Some early-season heat records may also be challenged this week, as searing inland temperatures move eastwards.
Sydney, for instance, is forecast to reach 39 degrees on Friday, while mid-40s readings are expected in a region stretching from South Australia to the western areas of NSW, Queensland and Victoria.
Driving global temperatures higher this year is the big El Nino event in the Pacific. During such years, wind patterns shift, allowing unusual heat to beat up in the central and eastern equatorial areas.
The US National Oceanic and Atmospheric Administration (NOAA) said a six million-square kilometre region on the Pacific, dubbed Nino3.4, had warmed by more than 2 degrees.
The heat required to warm just the top two metres of that region by that amount would require 100 quadrillion kilojoules, NOAA's Emily Becker said in a website post. That's 100 followed by 15 zeros. That tally is about equal to the total energy consumed each year in the US, she said.
The current El Nino continues to strengthen and is expected to peak either late this year or early next year, according to NOAA. The view is similar to one released by the Bureau of Meteorology last week.
The event is likely to break up by late autumn or early winter in the southern hemisphere although there are some signs it may linger longer than expected because of exceptionally warm conditions in the northern Pacific.
The El Nino ranks as the second strongest on record according to data going back to 1950, NOAA said.
Hot days ahead in the city
WEDNESDAY
33Âº - Sunny
THURSDAY
30Âº - Partly cloudy
FRIDAY
39Âº - Hot and sunny