Weather Calculators
Calculate wind chill, heat index, and dew point with free online weather calculators. Understand how temperature, humidity, and wind affect how conditions actually feel.
Wind Chill Calculator
Calculate the wind chill temperature based on actual temperature and wind speed.
Heat Index Calculator
Calculate the heat index (feels-like temperature) from air temperature and relative humidity.
Dew Point Calculator
Calculate the dew point temperature from air temperature and humidity to assess comfort.
About Weather Calculators
Our weather calculators help you understand the real-world impact of weather conditions beyond what a simple thermometer reading shows. Temperature alone does not tell the full story — wind, humidity, and moisture all dramatically affect how weather feels and its potential health impacts.
The Wind Chill Calculator determines the perceived temperature when wind combines with cold air. Wind strips heat from exposed skin faster than still air, making a 20°F day with 25 mph winds feel like -1°F. This calculation is essential for winter safety planning.
The Heat Index Calculator shows the perceived temperature when humidity combines with high heat. High humidity prevents sweat from evaporating efficiently, making a 95°F day with 70% humidity feel like 124°F — well into the danger zone for heat-related illness.
The Dew Point Calculator determines the temperature at which moisture condenses from the air. Dew point is the most reliable indicator of how humid conditions actually feel, as it measures the absolute moisture content rather than relative humidity, which changes with temperature.
Frequently Asked Questions
What is wind chill and how is it calculated?
Wind chill is the perceived decrease in air temperature felt by the body due to wind. The NWS Wind Chill Temperature Index uses air temperature and wind speed to calculate how cold it actually feels. The formula accounts for the rate of heat loss from exposed skin.
What is the heat index?
The heat index, also known as the apparent temperature, combines air temperature and relative humidity to indicate how hot it actually feels. High humidity reduces the body's ability to cool through evaporation, making the effective temperature much higher than the actual air temperature.
What does dew point tell you about weather?
Dew point indicates the temperature at which air becomes saturated and moisture begins to condense. A higher dew point means more moisture in the air. Dew points above 65°F feel humid, above 70°F feel oppressive, and above 75°F are extremely uncomfortable for most people.
When should I worry about wind chill?
Wind chill becomes dangerous when it drops below -20°F, which can cause frostbite on exposed skin in as little as 30 minutes. At wind chills below -40°F, frostbite can occur in under 10 minutes. Always limit exposed skin time in these conditions.
How do weather calculators help with safety?
Weather calculators help assess real danger levels beyond raw temperature readings. They help you decide when to limit outdoor activities, what to wear, hydration needs, and when conditions pose genuine health risks from hypothermia, frostbite, heat exhaustion, or heat stroke.