Input data below to calculate heat index using Relative Humidity.
Heat Index Calculator (Relative Humidity)
The Heat Index is a measure that combines air temperature and relative humidity to determine how hot it actually feels like to the human body. Often referred to as the “apparent temperature” or “feels like” temperature, it gives a better indication of the discomfort or health risks associated with the weather than temperature alone, especially in summer conditions.
Here’s how it works:
- Temperature: This is the actual air temperature measured in degrees, typically Fahrenheit or Celsius.
- Humidity: This is the amount of moisture in the air, expressed as a percentage. High humidity can inhibit the body’s ability to cool down through sweating because the air is already saturated with water vapor, reducing the effectiveness of sweat evaporation.
When these two factors are high, the Heat Index will be significantly higher than the actual temperature, indicating a higher risk of heat-related illnesses like heatstroke, heat exhaustion, or heat cramps. For example:
- If the temperature is 90°F (32°C) with 70% humidity, the Heat Index might be around 105°F (41°C), making it feel much hotter than it actually is.
- At 88°F (31°C) with 100% humidity, the Heat Index could rise to 112°F (44°C), posing a severe risk for outdoor activities.
The Heat Index is calculated using a formula or chart developed by the National Weather Service in the United States, although similar indices exist in other countries.
Heat Index vs. Wet Bulb Globe Temperature (WBGT):
- Heat Index:
- Measures how hot it feels based on temperature and humidity.
- Used for public health warnings about heat-related risks.
- Doesn’t account for solar radiation, wind, or cloud cover.
- Wet Bulb Globe Temperature (WBGT):
- Considers temperature, humidity, solar radiation, and wind.
- Used for safety in sports, military, and work settings, to manage heat stress during activity.
- Requires more complex equipment to measure in real-time, but can be monitored using advanced real-time weather analysis data and intelligence.
Main Differences:
- Complexity: WBGT is more comprehensive, capturing a broader range of environmental factors.
- Application: Heat Index for general public awareness; WBGT is more suitable for specific activity safety.
- Equipment: WBGT needs specialized tools and calculations to measure observations and forecasts; Heat Index only needs temperature and humidity data.