1. What is Relative Humidity?

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

2. How Does the Calculator Work?

The calculator uses the Magnus formula approximation:

Where:

• \( RH \) — Relative Humidity (%)
• \( T_d \) — Dry bulb temperature (°C)
• \( T_{dp} \) — Dew point temperature (°C)

Explanation: The equation approximates the relationship between temperature difference and humidity using empirically derived constants.

3. Importance of RH Calculation

Details: Accurate RH measurement is crucial for weather forecasting, comfort control in buildings, industrial processes, and preserving materials sensitive to moisture.

4. Using the Calculator

Tips: Enter both temperatures in Celsius. Dry bulb temperature must be greater than or equal to dew point temperature for valid results.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between RH and absolute humidity?
A: RH is temperature-dependent (relative to saturation), while absolute humidity measures actual water vapor content (g/m³) regardless of temperature.

Q2: Why does RH change with temperature?
A: Because warm air can hold more water vapor than cold air. The same amount of moisture results in lower RH at higher temperatures.

Q3: What is considered comfortable RH for humans?
A: Typically 30-60%. Below 30% can cause dryness, above 60% promotes mold growth and feels muggy.

Q4: How accurate is this approximation?
A: The Magnus formula is accurate to within ±0.4% RH for temperatures between -20°C and 50°C.

Q5: Can I calculate dew point from RH and temperature?
A: Yes, the equation can be rearranged to solve for dew point when you know RH and dry bulb temperature.