Calculate Heat Index, Humidex, and Dew Point with visual alerts.
Our advanced Temperature & Humidity Index Calculator is an essential meteorological tool for weather enthusiasts, outdoor workers, athletes, event planners, and health professionals assessing environmental comfort and safety conditions. Whether you're planning outdoor activities, assessing heat stroke risk, monitoring workplace safety, studying climate patterns, or optimizing indoor comfort, this calculator provides precise heat index and comfort level calculations based on scientific formulas.
Calculate Heat Index (feels-like temperature), Humidex comfort levels, Dew Point temperature, Relative Humidity effects, Heat risk categories, and Optimal comfort zones with our comprehensive weather analysis tool. Perfect for personal use, occupational safety, sports planning, and meteorological studies.
Uses official NOAA/NWS Heat Index formula and Rothfusz regression equation for precise calculations. Includes both Celsius and Fahrenheit scales with proper conversion algorithms.
Identifies heat-related illness risks: Heat cramps, Heat exhaustion, Heat stroke. Provides safety guidelines for vulnerable groups (elderly, children, outdoor workers).
Calculates Heat Index, Humidex, Apparent Temperature, Dew Point, Wet Bulb Temperature, and THSW Index (Temperature-Humidity-Sun-Wind) for comprehensive analysis.
Recommends optimal times for outdoor activities, sports events, construction work, and agricultural operations based on temperature-humidity comfort levels.
Used by meteorologists, athletes, outdoor workers, event planners, and health professionals worldwide. No registration required - calculate heat index and comfort levels instantly!
Heat Index (also called "feels-like temperature") combines air temperature and relative humidity to indicate how hot it feels to the human body. Formula: HI = -42.379 + 2.04901523T + 10.14333127R - 0.22475541TR - 6.83783×10⁻³T² - 5.481717×10⁻²R² + 1.22874×10⁻³T²R + 8.5282×10⁻⁴TR² - 1.99×10⁻⁶T²R² (where T=temperature°F, R=relative humidity%). Our calculator uses this exact formula.
Danger zones: Extreme Caution: 90°F (32°C) with 60% humidity (HI=100°F/38°C), Danger: 95°F (35°C) with 60% humidity (HI=114°F/46°C), Extreme Danger: 100°F (38°C) with 55% humidity (HI=124°F/51°C). Heat stroke becomes likely above HI=105°F (41°C). Our calculator identifies these risk levels.
Ideal indoor comfort: Temperature: 20-24°C (68-75°F) with Humidity: 40-60%. Optimal outdoor comfort: Temperature: 18-27°C (64-81°F) with Humidity: 30-70%. Dew point below 16°C (60°F) feels comfortable, above 21°C (70°F) feels oppressive. Our calculator shows your current comfort level.
High humidity reduces sweat evaporation, making you feel hotter. Example: 90°F (32°C) with 10% humidity feels like 85°F (29°C), but same temperature with 90% humidity feels like 122°F (50°C)! Low humidity can make cold feel colder due to faster heat loss. Our calculator quantifies these effects precisely.