How to Use Wet Bulb Temperature Calculator
The Wet Bulb Temperature Calculator estimates the wet-bulb temperature Tw — the lowest temperature air can reach by evaporative cooling at the current humidity. It is essential for heat-stress safety and HVAC design.
- Enter dry-bulb temperature T — In °C.
- Enter relative humidity RH — As a percentage, 0–100.
- Read Tw — The Wet Bulb Temperature Calculator returns Tw and the wet-bulb depression T − Tw.
Formula & Theory — Wet Bulb Temperature Calculator
The Wet Bulb Temperature Calculator uses the widely cited Stull (2011) empirical formula:
Tw = T·atan[0.151977·√(RH + 8.313659)]
+ atan(T + RH) − atan(RH − 1.676331)
+ 0.00391838·RH^1.5·atan(0.023101·RH) − 4.686035| Symbol | Meaning |
|---|---|
| Tw | Wet-bulb temperature (°C) |
| T | Dry-bulb temperature (°C) |
| RH | Relative humidity (%) |
Assumptions and Limits
The Wet Bulb Temperature Calculator is calibrated for standard sea-level pressure (1013 hPa). At significantly different elevations or pressures, use a psychrometric chart or full Magnus-formula calculation for better accuracy.
Use Cases for Wet Bulb Temperature Calculator
- Occupational safety — Compute WBGT-style heat-stress indicators.
- Evaporative cooling — Predict outlet temperature of swamp coolers.
- Meteorology — Identify dangerous humid-heat events.
- HVAC — Design cooling towers and air-handling coils.
The Wet Bulb Temperature Calculator delivers a fast, reliable estimate without lookup tables.