General Science of the Day
What is humidity? (Meteorological Instruments)

Humidity is the amount of moisture in the air.
According to the Technical Regulations published by the World Meteorological Organization, humidity can be expressed in six ways: mixing ratio, specific humidity, vapor pressure, absolute humidity, relative humidity, and dew-point temperature.

Report on Sunspot Observations
General Info of the Day
Date 2019-02-17
Moon Phase of the Day
Astronomy phenomenon
Sunrise and Sunset, Moonrise and Moonset