The average temperature of almost 7.5C is 0.5C more than the previous highest, which was recorded in 2014.
“It is partly related to global warming. The other week, the WMO [World Meteorological Organization, editor's note] reported that 2020 will be one of the two warmest years on the global scale,” Erik Kjellström, professor of climatology at Sweden's national weather agency SMHI, told the TT newswire.
“It was only May and July that were a little colder than usual.”
He added that there was “nothing positive” about the news, which is linked to climate change.
SMHI worked out the statistics by compiling data from 35 of its weather stations across Sweden, which all had available data going back to the 1860s.
At Kalix and Gävle, northern Dalarna and Lake Hjälmaren the average temperature was around 3C higher than normal.