Earth turned up the heat in June, smashing high temperature records for both the month and the first half of the year.

Off-the-charts heat is "getting to be a monthly thing," said Jessica Blunden, a climate scientist at the US' National Oceanic and Atmospheric Administration. June was the fourth month in 2015 that set a record, she said, adding, "There is almost no way that 2015 isn't going to be the warmest on record."

NOAA calculated that the world's average temperature in June hit 16.33 C, breaking the record set last year by 0.12 C.