Wet Bulb Temperature Calculator
Free wet bulb temperature calculator using Stull's formula. Determine heat stress risk and human survivability limits based on temperature and humidity.
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Calculate Wet Bulb Temperature
Wet bulb temperature (WBT) is a critical measure combining heat and humidity to assess true heat stress risk. It represents the lowest temperature achievable through evaporative cooling and determines whether the human body can effectively cool itself through sweating.
What Is Wet Bulb Temperature?
Wet bulb temperature is the temperature reading when a thermometer bulb is covered with a wet cloth and exposed to air flow. It accounts for both air temperature and humidity, making it the most accurate measure of heat stress on the human body. Above 35°C (95°F) wet bulb, even healthy humans cannot survive prolonged exposure.
Stull's Formula (2011)
Tw = T × atan[0.151977(RH + 8.313659)^0.5] + atan(T + RH) - atan(RH - 1.676331) + 0.00391838(RH)^1.5 × atan(0.023101 × RH) - 4.686035Why Calculate Wet Bulb Temperature?
Heat Stress Assessment
Wet bulb is the gold standard for assessing dangerous heat conditions for humans.
Climate Research
Scientists use wet bulb to study climate change impacts on human habitability.
Workplace Safety
OSHA and safety organizations use wet bulb for outdoor work guidelines.
How to Use This Calculator
Common Applications
Sports & Athletics
Teams use wet bulb to decide when outdoor practice is too dangerous.
Military Operations
Armed forces monitor wet bulb for training and deployment decisions.
Construction & Labor
Contractors use wet bulb to protect workers from heat illness.
Climate Adaptation
Cities use wet bulb projections to plan for extreme heat events.
Frequently Asked Questions
Above 26°C (79°F) requires caution. Above 32°C (90°F) is dangerous for strenuous activity. Above 35°C (95°F) is the human survivability limit - even healthy people in shade cannot survive prolonged exposure.