Is there a relationship between humidity and temperature?

The short answer is: Yes, the humidity of the air is related to the temperature.

The humidity of air is divided into absolute humidity, relative humidity and humidity ratio.

Absolute humidity refers to the weight of water contained in air per unit volume, generally expressed in mg/L.

Relative humidity refers to the ratio of absolute humidity to the maximum possible humidity (saturated water vapor content) at this temperature, which is generally expressed as a percentage. This is the humidity used in the weather forecast.

Humidity ratio = the weight of water in the air/the weight of (air+water), which is also generally expressed as a percentage.

With the increase of temperature, the water content in the air (that is, saturated water vapor content) also increases. With enough water, the air will be wetter in warm weather than in cold weather.

In a closed environment (such as indoors) or when water is scarce (such as desert), the absolute humidity generally does not change with the increase of temperature. With the increase of temperature, the maximum possible absolute humidity (saturated water vapor content) increases, so the relative humidity decreases. So turning on the heating at home in winter will make people feel very dry.

If the relative humidity is high (close to saturation), with the decrease of temperature, the maximum possible absolute humidity will also decrease, and the excess water in the air will solidify into water, thus reducing the absolute humidity. This is why air conditioners are also air dryers.