Back to Tools

Heat Index Calculator

Calculate what the temperature feels like with humidity

�C
%
Feels Like
100�F
10� hotter than actual
Caution Ext. Caution Danger Ext. Danger
??
Heat exhaustion possible with prolonged exposure.
Heat Stress Risk Moderate
Sunstroke Risk Low
Activity Level Reduce intensity
Hydration Drink extra water

Heat Index Chart

Heat Safety Tips

??
Stay Hydrated
Drink water regularly, even if not thirsty
??
Seek Shade
Stay indoors during peak heat hours (10am-4pm)
??
Dress Light
Wear loose, light-colored clothing
??
Avoid Alcohol
Alcohol increases dehydration risk

What is Heat Index?

The Heat Index (also known as "apparent temperature") is a measure of how hot it actually feels when humidity is factored in with the actual air temperature. High humidity reduces the body's ability to cool itself through sweating, making it feel hotter than the thermometer shows.

Common Use Cases

Weather Planning

Understand actual outdoor conditions before activities.

Health Safety

Assess heat stroke and heat exhaustion risk levels.

Exercise Planning

Determine safe conditions for outdoor workouts and sports.

Workplace Safety

Monitor conditions for outdoor workers and construction sites.

How It Works

1

Enter Temperature

Input the current air temperature in �F or �C.

2

Set Humidity

Adjust the relative humidity percentage.

3

View Heat Index

See what the temperature actually feels like with humidity.

4

Get Safety Advice

Review heat warnings and safety recommendations.