1. What is an RH and Dew Point Calculator?

Definition: This calculator determines the relative humidity based on temperature and dew point using the Magnus formula.

Purpose: It helps meteorologists, HVAC professionals, and others understand atmospheric moisture conditions.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( RH \) — Relative Humidity (%)
• \( T \) — Temperature (°C)
• \( T_d \) — Dew Point Temperature (°C)
• \( a \) — Constant (typically 17.27)
• \( b \) — Constant (typically 237.7)

Explanation: The formula compares the saturation vapor pressure at dew point temperature to that at ambient temperature.

3. Importance of RH Calculation

Details: Relative humidity affects comfort, health, building integrity, and many industrial processes.

4. Using the Calculator

Tips: Enter the temperature and dew point in °C. Constants a and b have default values (17.27 and 237.7 respectively).

5. Frequently Asked Questions (FAQ)

Q1: What is dew point temperature?
A: The temperature at which air becomes saturated with water vapor (100% RH).

Q2: Why are constants a and b needed?
A: These are empirical coefficients in the Magnus formula that vary slightly for different temperature ranges.

Q3: When would I change the constants?
A: For temperatures below 0°C, different constants might be used (e.g., a=21.87, b=265.5 for ice).

Q4: How accurate is this calculation?
A: The Magnus formula is accurate to within about ±0.4°C between 0°C and 50°C.

Q5: What's the relationship between RH and dew point?
A: Dew point is the temperature where RH would reach 100%, while RH indicates current moisture relative to maximum possible at current temperature.