The hottest was 1998, when the average temperature was up 0.99 degrees.
The average temperature was 10.9F (-11.7C) in Buffalo, beating the 1934 record of 11.4F.
At the same time, the UK average temperature was 8C, 4.1C above normal.
Through April, the global average temperature was 2.6°F (1.45°C) above the average from that earlier period.
Oklahoma's statewide average temperature was the warmest for any state for any month on record.
As Dr Andrew Glikson of the Australian National University has explained, during the Pliocene the world's average temperature was between 1C and 3C higher than it is today.
Dr. Michaels, in a recent paper, projected that the global average temperature was most likely to rise about 3 degrees from 1990 to 2100.
Peter Stott, at the Met Office's Hadley Centre, said 2015 was the first year global average temperature was more than 1C above pre-industrial levels.
However, it is well below the record set in 2006, the hottest UK month on record, when the average temperature was 17.8C.
The average temperature was -39C, 24 hours a day for seven days, so you couldn't dry anything: once something's wet it's wet for the whole expedition.
They alternated, though, with periods that make the modern tropics seem chilly: the planet's average temperature was sometimes as high as 50°C.
