Federal officials say July was Earth's hottest month on record, smashing old marks.
July's average temperature was 61.86 degrees Fahrenheit, beating the previous global mark set in 1998 and 2010 by about one-seventh of a degree. That's a large margin for weather records.
Records go back to 1880, but nine of the 10 hottest months on record have happened since 2005.
The first seven months of 2015 are the hottest January-to-July span on record.
Read More: Another Month, Another Global Heat Record Broken
National Oceanic and Atmospheric Administration climate scientist Jake Crouch says it is quite likely that 2015 will end up the hottest year on record, beating last year.
Crouch says this reaffirms that the Earth is warming, with a boost this year from an El Nino warming of the Pacific Ocean.