Weather tools

Wet Bulb and Dry Bulb to Relative Humidity

Calculates the relative humidity using the readings from a wet-bulb thermometer and a dry-bulb thermometer, which together measure the cooling effect of evaporation.

Before you use this tool

Use this if

  • Calculates the relative humidity using the readings from a wet-bulb thermometer and a dry-bulb thermometer, which together measure the cooling effect of evaporation.
  • You want a calculation that exposes its formula: Relative Humidity ≈ 100 - (((Dry Bulb Temperature - Wet Bulb Temperature) × 5) / 3)
  • You already have Dry Bulb Temperature, Wet Bulb Temperature values to enter.

Skip this if

  • You need an official emergency alert or life-safety instruction.
  • You need a certified professional forecast instead of a calculator estimate.
When to use or skip it

Use this if

  • Calculates the relative humidity using the readings from a wet-bulb thermometer and a dry-bulb thermometer, which together measure the cooling effect of evaporation.
  • You want a calculation that exposes its formula: Relative Humidity ≈ 100 - (((Dry Bulb Temperature - Wet Bulb Temperature) × 5) / 3)
  • You already have Dry Bulb Temperature, Wet Bulb Temperature values to enter.

Skip this if

  • You need an official emergency alert or life-safety instruction.
  • You need a certified professional forecast instead of a calculator estimate.