WASHINGTON (AP) — Another month, another global heat record smashed.

The National Oceanic and Atmospheric Administration says August's temperature of 61.74 degrees (16.52 Celsius) was the 16th month in a row that Earth set a record for the hottest month. NOAA monitoring chief Deke Arndt said it was also the hottest summer, with 2016 on pace to smash last year's record for the hottest year.

Records go back 137 years.

The announcement came on a day when 375 members of the National Academy of Sciences, including Stephen Hawking and 30 Nobel laureates, released an open letter urging American leaders not to pull out of an international agreement to curb global warming. Organizer and MIT climate scientist Kerry Emanuel said the scientists wrote the letter in response to the Republican party platform.