Hygrometer Barometer is a popular free humidity meter application available for iPhone. It provides a simple and convenient way to measure the relative humidity of your current location using GPS. The app displays the humidity as a percentage, allowing you to track and monitor the humidity levels in your area.

One of the key features of Hygrometer Barometer is its calculation function, which uses a formula to determine the discomfort index (DI) based on the humidity and the degree of Celsius. This can be helpful for assessing the overall comfort level in your environment.

In addition to measuring humidity, Hygrometer Barometer also offers a barometric function that utilizes the pressure sensor in iPhone 6 and later models. This feature allows you to track barometric pressure, which can be useful for weather forecasting and understanding atmospheric conditions.

Please note that Hygrometer Barometer provides measurements for outdoor humidity, rather than indoor humidity. It can serve as a reference for choosing appropriate clothing based on the weather conditions in your area. However, do keep in mind that certain areas may be excluded from the app's coverage.

Overall, Hygrometer Barometer is a simple and popular free humidity meter application that offers convenient measurements of relative humidity and barometric pressure. It can be a useful tool for those who are interested in monitoring and understanding the humidity levels in their environment.