The temperature hit 100 at Philadelphia International Airport, breaking the previous record of 99, set in 1953.
It marked the second time this year that the temperature reached triple digits. It made it to 101 on July 7, as loyal reader Larry Tollen pointed out. Today's heat index got as high as 106.
Since the official temperature also made it to 100 in the previous two summers, this makes only the third time in the period of record that the century mark was reached in three consecutive years.
The last such streaked occurred during the summers of 1993, '94, and 95, and before that, 1953, '54, and '55. The records go back to 1874.
Hitting 100 isn't all that easy in Philadelphia, where the summers typically brew humid air masses that force the sun to use some of its energy to evaporating water.
In ultra-humid Miami, for example, the temperature has hit 100 on only one date in the period of record, which dates to 1895.
In Philly, the high reaches 100 about once every four summers.