Heat Index Calculator
This calculator estimates the "feels like" temperature on hot days by combining air temperature with relative humidity or dew point.
Use Relative Humidity
Use Dew Point Temperature
What is the Heat Index?
The heat index, also known as humiture, is a measure of how hot it really feels when relative humidity is combined with the air temperature. This is different from the actual air temperature because a higher relative humidity reduces our body's ability to cool itself through sweating. When sweat doesn't evaporate as quickly, we feel hotter.
Potential Effects of Heat Index
High heat index values can have serious medical effects, as the body's cooling system is hindered. This can lead to dehydration and overheating. Below are the possible complications at different heat index values.
| Heat Index (Celsius) | Heat Index (Fahrenheit) | Health Risk |
|---|---|---|
| 27-32°C | 80-90°F | Caution: Fatigue is possible with prolonged exposure and activity. |
| 32-41°C | 90-105°F | Extreme Caution: Heat cramps and heat exhaustion are possible. |
| 41-54°C | 105-130°F | Danger: Heat exhaustion is likely; heat stroke is probable with continued activity. |
| Over 54°C | Over 130°F | Extreme Danger: Heat stroke is imminent. |
Note: Exposure to direct, full sunshine can increase heat index values by up to 14°F (8°C).