Calculate Humidity From Temperature

Relative Humidity Formula:

\[ RH = 100 \times \frac{\exp\left(\frac{17.625 \times T_d}{243.04 + T_d}\right)}{\exp\left(\frac{17.625 \times T}{243.04 + T}\right)} \]

Relative Humidity (RH):

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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 that the air could hold at that temperature, expressed as a percentage. It's a key parameter in meteorology, HVAC, and various industrial processes.

2. How Does the Calculator Work?

The calculator uses the relative humidity formula:

\[ RH = 100 \times \frac{\exp\left(\frac{17.625 \times T_d}{243.04 + T_d}\right)}{\exp\left(\frac{17.625 \times T}{243.04 + T}\right)} \]

Where:

\( RH \) — Relative Humidity (%)
\( T_d \) — Dew Point Temperature (°C)
\( T \) — Air Temperature (°C)
\( \exp \) — Exponential function

Explanation: This formula calculates relative humidity based on the relationship between dew point temperature and air temperature, using the Magnus-Tetens approximation for saturation vapor pressure.

3. Importance of Humidity Calculation

Details: Accurate humidity calculation is essential for weather forecasting, climate control systems, agricultural planning, industrial processes, and maintaining comfortable and healthy indoor environments.

4. Using the Calculator

Tips: Enter dew point temperature and air temperature in degrees Celsius. Both values should be within typical atmospheric ranges (-50°C to 60°C).

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between dew point and relative humidity?
A: Dew point is the temperature at which air becomes saturated with water vapor, while relative humidity is the percentage of moisture in the air relative to its maximum capacity at that temperature.

Q2: Why does relative humidity change with temperature?
A: Warmer air can hold more moisture than cooler air. So when temperature increases without adding moisture, relative humidity decreases, and vice versa.

Q3: What is considered comfortable relative humidity for humans?
A: Generally, 30-50% relative humidity is considered comfortable for most people. Levels below 30% can cause dryness, while above 60% can promote mold growth.

Q4: How accurate is this calculation method?
A: The Magnus-Tetens formula provides good accuracy for most practical purposes within typical atmospheric temperature ranges, with an error typically less than 0.5%.

Q5: Can this formula be used for temperatures below freezing?
A: Yes, the formula works for sub-zero temperatures, though the accuracy may slightly decrease for very low temperatures below -20°C.