A humidity calculation is a mathematical formula used in meteorology to determine properties like dewpoint, relative humidity, or heat index. All of these calculations involve the amount of water in the air in the form of vapor, which can have an impact on comfort, how equipment performs, and weather. Research facilities can take measurements that provide information about some of these properties, and in other cases, calculations are required to come up with meaningful results. It is also possible to reverse the results of calculations to find out the properties that went into them.
Humidity plays an important role in the climate. When the air is more humid, people may feel more uncomfortable, as it can make the environment feel warmer or colder than it really is. It can also interfere with the function of equipment that doesn’t like high moisture levels, and can cause problems like molding, peeling, swelling, and cracking. Researchers can use a humidity calculation to determine various values of interest.
One important factor in calculations is temperature, and another is the dewpoint, which represents the point at which the air would cool enough to force the water inside to precipitate out. This has a direct impact on relative humidity. If the dewpoint and the current temperature are close, the air is highly saturated with water, and would have a high relative humidity measurement. When these points are very distant, the relative humidity is much lower and the air can feel dry.
Other humidity calculation tools can determine air density, absolute humidity, and other properties of interest. These may need to be adjusted to compensate for factors like altitude, which can reduce air pressure and cause flaws if calculations designed for use at sea level are employed. Scientific observation stations can return raw data and may have computer systems to perform basic humidity calculations. People can also work backward from known information to make a humidity calculation; if they know the relative humidity and either the dewpoint or current temperature, for example, they can figure out the unknown value.
A number of humidity calculation utilities can be found online that are free to use. It is important to pay attention to whether measurements are made in Fahrenheit or Celsius, as a mistake can skew the results. It is also possible to directly consult formulas and perform the calculations by hand or with the assistance of a basic calculator. People who regularly make observations and conduct humidity research may memorize formulas so they can quickly calculate critical information.