Wet Bulb Calculator: Calculate Wet Bulb Temperature from Dry Bulb & Humidity

Wet bulb temperature is a fundamental concept in thermodynamics, meteorology, and HVAC (Heating, Ventilation, and Air Conditioning) systems. It represents the lowest temperature that can be achieved by evaporating water into the air at constant pressure. Our Wet Bulb Calculator makes it easy to calculate wet bulb temperature from dry bulb temperature and relative humidity using established psychrometric formulas.

The wet bulb temperature is always lower than or equal to the dry bulb temperature (ambient air temperature). The difference between these temperatures depends on the relative humidity: when humidity is 100%, the wet bulb and dry bulb temperatures are equal. As humidity decreases, the wet bulb temperature becomes lower, indicating the air's capacity to absorb moisture through evaporation.

Our Wet Bulb Calculator is designed for simplicity and accuracy. Follow these steps to get your calculation:

1. Enter Dry Bulb Temperature: Input the ambient air temperature (the temperature you would read on a standard thermometer)
2. Enter Relative Humidity: Input the relative humidity as a percentage (0-100%)
3. Select Temperature Unit: Choose your preferred unit (°C, °F, or K)
4. Click Calculate: The calculator will instantly compute the wet bulb temperature

The calculator uses Stull's psychrometric formula, which provides accurate results for most practical applications in HVAC, meteorology, and thermal comfort analysis.

The wet bulb temperature is calculated using psychrometric relationships that account for the interaction between temperature, humidity, and evaporation. The formula used in our calculator is based on Stull's approximation:

This formula provides accurate results for temperatures ranging from -50°C to 60°C and relative humidity from 0% to 100%, making it suitable for most real-world applications.

Wet bulb temperature calculations are essential in numerous fields and applications:

• HVAC Systems: Designing and optimizing air conditioning and heating systems for energy efficiency
• Meteorology: Understanding weather patterns, heat waves, and climate conditions
• Thermal Comfort: Assessing human comfort levels in indoor and outdoor environments
• Industrial Processes: Controlling humidity and temperature in manufacturing and storage facilities
• Agriculture: Managing greenhouse environments and crop storage conditions
• Sports and Safety: Evaluating heat stress and determining safe conditions for outdoor activities
• Energy Efficiency: Optimizing cooling tower performance and evaporative cooling systems

Understanding the relationship between different temperature measurements is crucial:

• Dry Bulb Temperature: The ambient air temperature measured by a standard thermometer. This is the temperature you typically see in weather reports.
• Wet Bulb Temperature: The lowest temperature achievable through evaporative cooling. It's always less than or equal to the dry bulb temperature.
• Dew Point Temperature: The temperature at which air becomes saturated and condensation begins. It's always less than or equal to the wet bulb temperature.

The relationship is: Dry Bulb ≥ Wet Bulb ≥ Dew Point. When relative humidity is 100%, all three temperatures are equal.

Our calculator supports multiple temperature units for your convenience:

• Celsius (°C): The standard metric unit, commonly used in scientific and international applications
• Fahrenheit (°F): Commonly used in the United States for weather and HVAC applications
• Kelvin (K): The absolute temperature scale used in scientific calculations

Relative Humidity: Always entered as a percentage (0-100%). A value of 0% means completely dry air, while 100% means the air is fully saturated with water vapor.

Example 1: Comfortable Indoor Environment

Calculate the wet bulb temperature for a room at 25°C with 50% relative humidity:

Example 2: Hot and Humid Conditions

Calculate the wet bulb temperature for outdoor conditions at 35°C with 80% relative humidity:

Example 3: Dry Desert Conditions

Calculate the wet bulb temperature for desert conditions at 40°C with 20% relative humidity:

Wet bulb temperature is critical for assessing heat stress and safety conditions. The wet bulb globe temperature (WBGT) index, which incorporates wet bulb temperature, is used to determine safe working conditions:

• Low Risk (< 25°C WBGT): Normal activities can proceed with standard precautions
• Moderate Risk (25-28°C WBGT): Increased rest periods and hydration required
• High Risk (28-31°C WBGT): Strenuous activities should be limited, frequent breaks necessary
• Extreme Risk (> 31°C WBGT): Outdoor activities should be suspended or moved indoors

Understanding wet bulb temperature helps prevent heat-related illnesses and ensures safe working and living conditions.

Understanding and calculating wet bulb temperature is essential for anyone working with HVAC systems, meteorology, thermal comfort, or heat stress assessment. Our Wet Bulb Calculator simplifies these complex psychrometric calculations, making it easy to determine wet bulb temperature from dry bulb temperature and relative humidity.

Whether you're designing an HVAC system, assessing thermal comfort, or evaluating safety conditions, accurate wet bulb temperature calculations are crucial. Explore our other physics calculators, such as our Velocity Calculator or Acceleration Calculator, for more physics calculations.