It measures with the sensors of barometer, thermometer (thermometer), hygrometer, and illuminometer built into the smart phone.
It may not have a built-in sensor, but in that case, it retrieves information from the Internet based on the current location and displays the nearest weather information measurements.

The following sensor measurement values are displayed.
・Atmospheric pressure
・Thermometer (thermometer)
・Hygrometer
・Illuminance meter (brightness)

It also displays the information of the observatory data.
・Weather in current location
・Precipitation amount of current location(rainfall)
・Wind speed of current location
・Maximum temperature on the day
・Minimum temperature on the day

All measurements are displayed on a single screen, so it's simple and easy to see.
It's all free. It's a free app.
Please use this product to prevent heat stroke and prevent headaches.