1. What is Relative Humidity?

Relative Humidity (RH) is a measure of how much water vapor is in the air compared to the maximum amount the air could hold at that temperature. It's expressed as a percentage.

2. How Does the Calculator Work?

The calculator uses the Relative Humidity formula:

Where:

• \( RH \) — Relative Humidity (%)
• \( P_v \) — Vapor pressure (Pa)
• \( P_{sat} \) — Saturation vapor pressure (Pa)

Explanation: The formula calculates what percentage the actual vapor pressure is of the saturation vapor pressure at the same temperature.

3. Importance of RH Calculation

Details: Relative humidity is important for weather forecasting, comfort assessment, industrial processes, and maintaining proper conditions in buildings and storage facilities.

4. Using the Calculator

Tips: Enter vapor pressure and saturation pressure in Pascals (Pa). Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between absolute and relative humidity?
A: Absolute humidity measures the actual amount of water vapor in the air (g/m³), while relative humidity measures how close the air is to saturation (%).

Q2: What are typical RH values?
A: Comfortable indoor RH is typically 30-50%. Below 30% may feel dry, above 60% may feel humid and promote mold growth.

Q3: How does temperature affect RH?
A: Warmer air can hold more moisture, so RH changes with temperature even if the actual moisture content stays the same.

Q4: What instruments measure RH?
A: Hygrometers and psychrometers are common instruments for measuring relative humidity.

Q5: Why is RH important in weather forecasting?
A: RH helps predict precipitation, fog formation, and is important for understanding human comfort and heat index.