Wet Bulb Calculator
Calculate wet-bulb temperature, dew point, and evaporative cooling potential
Use local station pressure when available, or keep the sea-level default.
Calculation Steps
How Wet Bulb Is Calculated
Wet bulb combines temperature, humidity, and air pressure to estimate evaporative cooling.
Evaporative cooling
Lower humidity allows more evaporation, so wet-bulb temperature falls farther below the dry air temperature.
Pressure effect
Air pressure changes how much cooling evaporation can produce. The default is close to standard sea-level pressure.
Heat context
Wet bulb is useful context for humid heat, but it does not replace WBGT, shade, wind, sun exposure, activity, clothing, or health guidance.
Wet Bulb Examples
Compare how humidity and pressure affect wet-bulb temperature.
Warm humid day
86°F with 50% humidity at 29.92 inHg gives a wet bulb near 72°F.
Metric weather reading
30°C with 50% humidity at 1013 hPa gives a wet bulb near 22°C.
Saturated air
At 100% relative humidity, wet bulb and air temperature are nearly the same.
Wet Bulb Calculator FAQ
Common questions about wet bulb temperature, humidity, pressure, and heat stress.
What is wet bulb temperature?
Wet bulb temperature estimates the lowest temperature air can reach by evaporative cooling at the entered humidity and pressure.
How is wet bulb different from dew point?
Dew point is the saturation temperature for the water vapor already in the air. Wet bulb also accounts for evaporative cooling and pressure.
Why does pressure matter?
Air pressure changes the psychrometric relationship between evaporation and cooling. Sea-level pressure is a good default for many quick estimates.
Is wet bulb the same as WBGT?
No. Wet bulb globe temperature also includes radiant heat, sun, wind, and globe temperature. This calculator estimates thermodynamic wet bulb only.
Can I use this for heat safety decisions?
Use it as educational context only. Follow local heat alerts, workplace rules, medical guidance, and measured conditions for safety decisions.