THSW Index Calculator
The THSW (Temperature Humidity Sunshine Wind) index is a comprehensive weather comfort index that combines temperature, relative humidity, wind speed, and solar radiation. Use this calculator to determine your comfort level and receive personalized health recommendations for current weather conditions.
Enter Weather Conditions
Range: -50°C to 70°C (-58°F to 158°F)
Range: 0% to 100%
Range: 0 to 200 km/h
THSW Index Results
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Enter weather conditions and click calculate to determine your comfort level.
About THSW Index Calculator
What is the THSW Index?
The THSW (Temperature Humidity Sunshine Wind) index is a comprehensive weather comfort index that combines temperature, relative humidity, wind speed, and solar radiation to provide a more accurate assessment of how weather actually feels. Unlike simple temperature readings, THSW accounts for multiple environmental factors that affect human comfort and health. It's particularly useful for outdoor activities planning, health recommendations, and understanding real weather impact.
Key Points About THSW Index
- •THSW provides a more realistic 'feels like' temperature than simple temperature readings
- •Higher THSW values indicate less comfortable conditions; lower values indicate better comfort
- •Wind speed significantly affects THSW, making it colder in winter and potentially cooling in summer
- •Humidity and sunshine also play important roles in determining actual comfort levels
Real-World Applications of THSW Index
- ✓Outdoor Activity Planning: Athletes and outdoor enthusiasts use THSW to determine safe conditions for running, cycling, hiking, and other activities
- ✓Health and Safety: Healthcare providers use THSW to identify vulnerable populations at risk during extreme weather events
- ✓Tourism and Events: Event organizers use THSW to plan outdoor events and recommend appropriate clothing to attendees
- ✓Agricultural Planning: Farmers use THSW to monitor crop conditions and plan irrigation and pest control timing
How to Use the THSW Index Calculator
Using this calculator is simple and provides instant insights into your comfort level based on current weather conditions. Follow these easy steps to get accurate THSW index results and personalized health recommendations.
Step-by-Step Instructions
- Step 1:Enter the current air temperature in your preferred unit (Celsius or Fahrenheit)
- Step 2:Input the relative humidity percentage (0-100%) measured at the same location and time
- Step 3:Enter the current wind speed in your preferred unit (km/h, mph, m/s, or knots)
- Step 4:Optionally, add cloud cover percentage (0-100%) for more accurate sunshine adjustment
Helpful Tips for Accurate Results
- 💡Always use measurements from the same location taken at approximately the same time for consistency
- 💡Wind speed has a major impact on THSW, especially in cold weather. Use the most recent wind speed data.
- 💡If you don't have exact cloud cover data, use 0% for clear skies and 100% for fully overcast conditions
THSW Index Formula and Calculation
The THSW index combines multiple weather parameters through scientific formulas to create a single comfort metric. Understanding the formula helps you appreciate how each factor contributes to your perceived comfort level.
THSW Calculation Method
THSW = Base Temperature + Humidity Adjustment + Wind Effect + Solar Radiation Adjustment
The calculator uses a sophisticated approach that applies the NWS Steadman heat index formula for warm temperatures (>20°C) and North American wind chill formula for cold temperatures (<10°C), with smooth blending for moderate temperatures. Wind speed is converted to a standard unit (km/h) before calculation to ensure consistency across all wind speed inputs.
Components of THSW Index
- Base Temperature: The starting point is the actual air temperature, which forms the foundation for THSW calculation
- Humidity Adjustment: Higher humidity reduces evaporative cooling, making warm temperatures feel even hotter. The heat index accounts for this effect.
- Wind Speed Effect: Wind enhances cooling in cold conditions (wind chill) but can increase evaporative cooling in hot, dry conditions
- Solar Radiation / Cloud Cover: Clear skies and direct sunlight can increase perceived temperature, while cloud cover reduces solar heating effect
Important Notes About THSW Calculation
- ⚠The formulas used are based on scientific research and provide reasonable accuracy for practical outdoor planning
- ⚠THSW is most accurate under normal conditions. Extreme or unusual weather patterns may require additional considerations
- ⚠Individual comfort perception varies based on acclimatization, clothing, activity level, and health status
THSW Index Examples
Here are real-world scenarios showing how different weather combinations affect the THSW index and comfort levels. These examples help illustrate why THSW provides more useful information than temperature alone.
Example 1: Mild Autumn Day
Given:
- • Temperature: 18°C (64°F)
- • Relative Humidity: 55%
- • Wind Speed: 15 km/h, Cloud Cover: 30%
Result:
THSW: 15°C - Cool but comfortable. Ideal conditions for outdoor activities with light jacket.
Example 2: Humid Summer Day
Given:
- • Temperature: 28°C (82°F)
- • Relative Humidity: 75%
- • Wind Speed: 5 km/h, Cloud Cover: 80%
Result:
THSW: 33°C - Hot and humid. Stay hydrated, take frequent breaks, wear light clothing, and seek shade.
Example 3: Windy Cold Day
Given:
- • Temperature: 2°C (36°F)
- • Relative Humidity: 45%
- • Wind Speed: 35 km/h, Cloud Cover: 90%
Result:
THSW: -5°C - Cold with significant wind chill. Requires warm winter clothing, gloves, and hat. Limit outdoor exposure.
Frequently Asked Questions About THSW Index
Get answers to common questions about the THSW index, how it's calculated, and how to use it for better outdoor planning and health decisions.
How does THSW differ from just temperature?▼
Temperature alone doesn't account for how weather actually feels. THSW combines temperature, humidity, wind, and sunshine to provide a comprehensive comfort index. For example, 25°C with low wind and low humidity feels very different from 25°C with high humidity and no wind. THSW captures these differences.
What is the ideal THSW range for outdoor activities?▼
The ideal THSW range is typically 15-25°C for most outdoor activities. Below 0°C requires specialized cold weather gear. Above 30°C, heat stress becomes a concern. The calculator provides specific recommendations based on your calculated THSW value.
Why does wind affect THSW so much?▼
Wind accelerates heat loss from exposed skin through convection. In cold conditions, this creates 'wind chill' making it feel much colder than the actual temperature. In hot, dry conditions, wind can increase evaporative cooling. This is why wind speed is a critical THSW component.
How accurate is the THSW calculator?▼
The calculator uses scientific formulas (NWS heat index and North American wind chill) that are reasonably accurate for outdoor planning. Accuracy depends on input data quality. For precise meteorological applications, consult professional weather services.
How often should I check the THSW index during the day?▼
THSW changes throughout the day as temperature, wind, humidity, and cloud cover vary. Check it regularly, especially before planning outdoor activities. Morning and afternoon THSW values can differ significantly, affecting activity safety and comfort.