If you're still wondering why the mixing ratio of the air calculator could be useful to you, here's a practical example. You could have noticed that increased humidity compromises your body's performance as it makes you experience the air temperature as higher than it actually is. Wind chill causes a similar (opposite) effect in winter.
Therefore, if you're planning to do some activity, whether it's just a pleasant hike or intensive exercise, it's good to know what will await you, especially if you're concerned with your scores, such as VO2 max.
Let's use data for San Antonio, Texas. On some day in June, the temperature was 81 °F (27.22 °C), with a dew point of 78 °F (25.56 °C) and pressure of 1006 mb. Have you noticed how close the air temperature was to the dew point? Because of that, we may expect that the air was close to being saturated with water vapor. Inputting the numbers into the calculator, we obtain the actual mixing ratio of 20.87 g/kg and a relative humidity of 90.34%, confirming our ansatz.
Phoenix, Arizona, on the contrary, was reported to have an air temperature of 88 °F (31.11 °C), a dew point of 54 °F (12.22 °C), and exactly the same pressure. This resulted in the mixing ratio of 8.92 g/kg, with a relative humidity of 30.55%. So although it was hotter, you most likely would've found it easier to exercise in Phoenix on that day than in San Antonio.
We've prepared a small mixing ratio chart. It illustrates how the mixing ratio would change depending on the dew point under the conditions in San Antonio, that is, air temperature of 80.6 °F (27°C) and pressure of 1006 mb:
It can also give you an idea of how increasing the vapor pressure would affect the mixing ratio since it depends on the dew point.
You could use a similar approach when considering your summer voyage or preparing for competition!
