Humidity & Temperature Calculator
Enter air temperature and relative humidity to estimate dew point, heat index, humidex, wet-bulb temperature, and comfort risk.
What this humidity temperature calculator does
Temperature alone does not tell you how hot or comfortable the air really feels. Moisture in the air changes how your body cools itself, how quickly sweat evaporates, and how safe conditions are for outdoor work or exercise. This calculator combines temperature and relative humidity to estimate practical weather and indoor comfort metrics in seconds.
By using one quick input set, you can see dew point, heat index, humidex, and wet-bulb temperature. These values are commonly used in weather forecasting, HVAC planning, health and safety checks, and everyday decisions like choosing workout times or adjusting home ventilation.
How to use the calculator
- Enter current air temperature.
- Select Celsius or Fahrenheit.
- Enter relative humidity percentage.
- Click Calculate to view all derived metrics.
The tool works best for normal weather and indoor environments. Values are estimates and should not replace official heat alerts, industrial monitoring equipment, or medical guidance.
Understanding the output values
Dew Point
Dew point is the temperature at which air becomes saturated and water vapor begins to condense. It is one of the best indicators of how muggy air feels.
- Below 10°C (50°F): typically dry
- 10–16°C (50–61°F): comfortable
- 16–21°C (61–70°F): humid to muggy
- Above 21°C (70°F): oppressive for many people
Heat Index
Heat index estimates how hot it feels to people when humidity is included, mainly in warm conditions. It is especially useful in summer safety planning because higher humidity can make moderate temperatures dangerous.
Humidex
Humidex is another “feels-like” measure, widely used in Canada. Like heat index, it rises as humidity rises, but uses a slightly different model based on vapor pressure.
Wet-Bulb Temperature
Wet-bulb temperature approximates the lowest temperature possible through evaporative cooling. It is important in athletics, occupational safety, and climate stress analysis. Very high wet-bulb values indicate reduced ability for the human body to cool itself.
Why humidity matters for comfort and health
Your body relies on sweat evaporation to remove heat. When humidity is high, evaporation slows, so core temperature can rise faster. This increases risk for heat exhaustion and heat stroke, particularly during physical activity, direct sun exposure, and limited airflow.
Low humidity can also be uncomfortable. Dry air may irritate skin, eyes, nose, and throat, and can worsen static electricity and respiratory irritation indoors. Comfort is generally best in a middle range of humidity.
Recommended indoor temperature and humidity targets
- Relative humidity: usually 30% to 50% for comfort and moisture control.
- Winter indoor temperature: often around 20–22°C (68–72°F).
- Summer indoor temperature: often around 23–26°C (73–79°F), depending on activity and ventilation.
If humidity is persistently high, consider dehumidification, better air circulation, and checking moisture sources. If it is too low, controlled humidification may improve comfort.
Formulas used by this tool
This calculator uses common approximation models:
- Dew Point: Magnus formula using air temperature and relative humidity.
- Heat Index: NOAA regression in Fahrenheit (with adjustment rules in valid ranges).
- Humidex: vapor pressure method from dew point.
- Wet-Bulb Temperature: Stull approximation for fast practical estimates.
Because these are model-based estimates, small differences from official weather station tools are normal.
Quick FAQ
Is 100% humidity always raining?
No. It means air is saturated at that temperature, but rain requires cloud formation and droplet growth conditions.
What is better for comfort: relative humidity or dew point?
Dew point is usually a better direct indicator of perceived mugginess because it reflects absolute moisture more consistently across temperatures.
Can I use this for workplace heat safety decisions?
Use it as a screening estimate only. For regulated safety environments, follow official WBGT and local occupational guidelines.