Given that people tend to misjudge air temperature when in the sun, due to radiation absorbed by the skin and clothing, I was skeptical of claims that the air temperature drops by 10 degrees F during a total eclipse of the sun (in that antiquated system of measurement used in the U.S.) .
I measured it during the eclipse in Brownsville, Oregon, USA, using a type K thermocouple and a calibrated HH506RA (Omega) to record shade temperature. The claims are correct! See attached.
Some of the measurement variation seems to be due to air currents, presumably bringing in air masses of different temperatures.
Totality was at about 10:21 AM