In the United States, barometric pressures are generally reported in inches of mercury (in.Hg)

. On a beautiful summer day in Chicago, the barometric pressure is 30.37 in.Hg
.Convert this pressure to atm
.

To convert inches of mercury to atmospheres, we first need to convert the pressure from inches of mercury to millimeters of mercury, and then to atmospheres.

1 atm = 760 mmHg

30.37 in.Hg x (25.4 mm/in) = 771.198 mmHg

Now, we can convert from millimeters of mercury to atmospheres:

771.198 mmHg x (1 atm / 760 mmHg) = 1.015 atm

So, the barometric pressure of 30.37 in.Hg in Chicago on a beautiful summer day is equivalent to 1.015 atm.