1. What is Relative Humidity?

Relative Humidity (RH) is the ratio of the current amount of water vapor in the air to the maximum amount possible at the current temperature, expressed as a percentage. It's a key parameter in meteorology, HVAC systems, and industrial processes.

2. How Does the Calculator Work?

The calculator uses the Relative Humidity formula:

Where:

• \( e \) — Actual vapor pressure (Pa)
• \( es \) — Saturation vapor pressure (Pa)
• \( RH \) — Relative Humidity (%)

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

3. Importance of Relative Humidity Calculation

Details: RH affects human comfort, building design, industrial processes, and weather forecasting. Proper humidity levels are crucial for health, material preservation, and many manufacturing processes.

4. Using the Calculator

Tips: Enter both vapor pressure values in Pascals (Pa). Both values must be positive numbers for the calculation to work.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between absolute and relative humidity?
A: Absolute humidity measures the actual water vapor content (g/m³), while relative humidity measures how close the air is to saturation at its current temperature.

Q2: What are typical relative humidity ranges?
A: Comfortable indoor RH is typically 30-50%. Below 30% can feel dry, above 60% can feel muggy and promote mold growth.

Q3: How does temperature affect relative humidity?
A: Warmer air can hold more moisture, so RH decreases as temperature rises (with constant moisture content) and increases as temperature falls.

Q4: What instruments measure relative humidity?
A: Hygrometers, psychrometers, and modern electronic sensors can measure RH directly.

Q5: Why is RH important in weather forecasting?
A: High RH near 100% indicates potential for fog, dew, or precipitation, while low RH increases fire danger and affects evaporation rates.