NEW YORK • Following a May that tied for the hottest on record, the United States is heading into a potentially blistering summer, with hotter than normal temperatures expected across almost the entire country into September, government researchers have said.
Meteorologist Dan Collins of the National Oceanic and Atmospheric Administration’s (NOAA) Climate Prediction Centre said on Thursday that for July, August and September across almost all the US, “the average temperatures are likely to be above normal” especially in the west and north-east.
The trends over the last few decades are clear. The most recent figures are in line with a general warming trend: Each decade since the 1960s has been warmer than the one before, and the five hottest years occurred in the second half of the last decade.
High temperatures were likeliest in the mid-Atlantic states, north-east and New England, and across much of the west, Rocky Mountains and south-west. Only a small part of the Midwest, centred on Missouri, has an equal chance of lower-than-normal temperatures, according to an analysis by the Climate Prediction Centre.
That warmth will likely mean that drought conditions, now felt by nearly a quarter of the country, will persist through the summer, NOAA scientists said.
Globally, last month was tied with 2016 for the hottest May on record, with average land and sea temperatures that were 0.95 deg C above the average dating back more than a century. Areas with the warmest average temperatures included Alaska, the south-western US, the Caribbean, parts of Western Europe and northern Asia.
But May was also cooler than average across much of the Plains and the East Coast, said Ms Karin Gleason, an NOAA climatologist.
It is now virtually certain that, globally, 2020 will be one of the five hottest years on record, she said. But it is less likely that 2020 will eclipse 2016 as the hottest ever. NOAA now estimates there to be a 50 per cent chance that 2020 will be a record breaker, down from about 75 per cent a month ago.
Mr Gavin Schmidt, director of the Goddard Institute for Space Studies at Nasa, said that the new information is in line with what is known about climate change.
“There is a long-term trend in temperatures driven by human activity that is going to lead to more and more records being broken,” he said. “Not every month, not every year – but this will keep happening as long as we continue to emit carbon dioxide.”
July is the hottest month of all on a global average, even though it is winter in the southern hemisphere. July 2019 was the hottest ever, with an average temperature about 1 deg C higher than the 20th century average for the month.
The five hottest Julys have occurred in the last five years, and nine of the 10 hottest have occurred since 2005.