Virtual Temperature Calculator

About the Virtual Temperature Calculator

Virtual temperature is the temperature dry air would need to have the same density as moist air at the same pressure. It accounts for the buoyancy effect of water vapor.

How to use

Enter the air temperature (°C) and mixing ratio (g/kg), then click Calculate.

Worked example

T = 25 °C, w = 10 g/kg → Tᵥ ≈ 26.8 °C.

How to use this calculator

1. Enter the air temperature in the tool's temperature field.
2. Enter the mixing ratio in the mixing ratio field using the units the tool expects.
3. Click calculate to get the virtual temperature and review the step-by-step result.

The formula explained

• \(\text{T}_v\) = virtual temperature
• \(T\) = actual air temperature
• \(q\) = mixing ratio

Step by step method

1. Start with the measured air temperature and mixing ratio for the same air parcel.
2. Use the calculator to apply the virtual temperature formula to those inputs.
3. Read the output as the temperature the air would have if its moisture effect were accounted for.
4. Use the step-by-step display to check how the result was built from the inputs.

Worked example

Suppose the air temperature is 300 K and the mixing ratio is 0.010.

1. Plug the values into \(\text{T}_v = T(1 + 0.61q)\): \(\text{T}_v = 300(1 + 0.61 \cdot 0.010)\).
2. Compute the moisture term: \(0.61 \cdot 0.010 = 0.0061\).
3. Add 1: \(1 + 0.0061 = 1.0061\), then multiply: \(300 \cdot 1.0061 = 301.83\).

Tips and common mistakes

• Make sure the temperature unit matches what the calculator expects, since Kelvin and Celsius are not interchangeable in the formula.
• Use the mixing ratio in the correct form, not relative humidity.
• Keep an eye on decimal placement, since mixing ratio values are often small.
• If the result looks odd, recheck that both inputs describe the same air parcel and are in consistent units.

Frequently asked questions