July 2019 been officially identified as the hottest on "record" is highly debatable. NOAA and NASA have been caught manipulating temperature data many, many times, so there is chaos as to the validity of average global temp. numbers.
A better question is to what is the cause of the wild temperature swings we are experiencing around the planet.
I believe that the Sun and its natural variations are the cause. The Sun's total solar irradiance affects Galactic Cosmic ray flux, which affects the Earth's cloud cover. Planetary orbital variations can affect the Sun's orbital spin, especially in the Sun's mid latitudes. The faster the spin the lower number of sunspots, the lower the TSI, solar wind speed, high density protons, Ultra violet rays and xrays hitting the Earth.
From NOAA's website for July 2019, it doesn't look over cooked to me.