Wind Chill / Heat Index Calculator

Name: Wind Chill / Heat Index Calculator
Author: Jitendra Kumar

Estimate feels-like temperature from air temperature, wind speed, relative humidity, and sun exposure.

Last Updated: May 2026

Air temperature

deg F

Temperature unit

Relative humidity

Wind speed

mph

Wind unit

Sun exposure

Full sun adds a planning estimate to heat-index conditions only.

Feels Like

108.3 deg F

Active Index

Heat index

Difference From Air

+16.3 deg F

Risk Level

Danger

Heat cramps, heat exhaustion, and heat stroke risk increase.

Measure	Result	Interpretation
Air temperature	92.0 deg F	Measured shade air temperature.
Wind speed	6.0 mph	Converted to mph for the NWS wind chill equation.
Relative humidity	65%	Used for heat index.
Wind chill	Not applicable	Defined at or below 50 deg F with wind above 3 mph.
Heat index	108.3 deg F	Used for hot and humid conditions, especially 80 deg F and above.
Full sun estimate	108.3 deg F	Adds up to 15 deg F when full sunshine is selected.

Wind chill range

Wind chill is defined for temperatures at or below 50 deg F and wind above 3 mph.

Heat index range

Heat index estimates how hot it feels when relative humidity is included.

Sun exposure

Full sunshine can make heat-index conditions feel up to 15 deg F hotter.

Weather Safety Notice

This calculator is an educational estimate and does not replace official forecasts, watches, warnings, advisories, or workplace heat/cold safety rules. For severe weather decisions, use your local National Weather Service forecast and emergency guidance.

Reviewed For Methodology, Labels, And Sources

Every CalculatorWallah calculator is published with visible update labeling, linked source references, and founder-led review of formula clarity on trust-sensitive topics. Use results as planning support, then verify institution-, policy-, or jurisdiction-specific rules where they apply.

Reviewed By

Jitendra Kumar, Founder & Editorial Standards Lead, oversees methodology standards and trust-sensitive publishing decisions.

Review editor profile

Topic Ownership

Sales tax and tax-sensitive estimate tools, Education and GPA planning calculators, Health, protein, and screening-formula pages, Platform-wide publishing standards and methodology

See ownership standards

Methodology & Updates

Page updated May 2026. Trust-critical pages are reviewed when official rates or rules change. Evergreen calculator guides are checked on a recurring quarterly or annual cycle depending on topic volatility.

Sources & methodology About the review process

How to Use the Wind Chill / Heat Index Calculator

Enter the measured air temperature, choose Fahrenheit or Celsius, then add wind speed and relative humidity. Select full sun when you want a rough heat-stress planning estimate for direct sunshine.

The calculator automatically decides whether wind chill, heat index, or actual air temperature is the active apparent-temperature result.

Step 1: Enter temperature
Use the outdoor shade air temperature and choose deg F or deg C.
Step 2: Add wind and humidity
Enter wind speed in your preferred unit and relative humidity as a percentage.
Step 3: Choose sun exposure
Use shade for standard heat-index values or full sun for a planning adjustment.
Step 4: Review the active index
Check whether the result is wind chill, heat index, sun-adjusted heat index, or actual air temperature.

How This Wind Chill / Heat Index Calculator Works

For cold conditions, the calculator uses the National Weather Service wind chill equation when air temperature is at or below 50 deg F and wind is above 3 mph. Wind speed inputs are converted to mph before the equation is applied.

For hot conditions, it uses the standard heat-index regression with air temperature and relative humidity. If full sun is selected, it adds a planning adjustment because direct sunshine can increase heat-index conditions.

When neither formula range applies, the calculator shows actual air temperature and explains that there is no active wind chill or heat index result for those inputs.

Wind Chill and Heat Index Guide

Formulas and Ranges

Measure	Formula or rule	Use
Wind chill	35.74 + 0.6215T - 35.75(V^0.16) + 0.4275T(V^0.16)	T is deg F and V is mph. Valid at or below 50 deg F with wind above 3 mph.
Heat index	NWS/Rothfusz heat-index regression	Uses air temperature in deg F and relative humidity percentage.
Full sun adjustment	heat index + up to 15 deg F	Used only as a planning estimate when full sunshine is selected.
Unit conversion	deg C = (deg F - 32) / 1.8	Inputs can be entered in Fahrenheit/Celsius and several wind speed units.

How to Interpret Results

Result state	Likely reason	What it means
Wind chill not shown	Temperature above 50 deg F or wind at/below 3 mph	The wind chill equation is outside its defined range.
Heat index not shown	Temperature below 80 deg F	Heat index is mainly used for hot conditions where humidity changes perceived heat.
Shade assumption	Standard heat-index values	Heat index values are generally intended for shady, light-wind conditions.
Full sun selected	Adds a planning estimate	Direct sun can make heat stress meaningfully worse than the shade value.

Use measured local conditions when possible. Airport weather, phone apps, and home weather stations can differ because wind, humidity, shade, pavement, elevation, and sun exposure vary over short distances.

Wind chill and heat index are both human comfort and safety indexes. They are useful for planning clothing, breaks, hydration, outdoor work, and activity intensity, but they are not substitutes for official alerts.

For basic unit changes, use the temperature converter. For home heating and cooling planning, compare this weather result with the BTU calculator.

Keep the research moving with Temperature Converter, BTU Calculator, Electricity Cost Calculator, and Target Heart Rate Calculator.

Frequently Asked Questions

Wind chill estimates how cold exposed skin feels in cold, windy conditions. Heat index estimates how hot it feels when humidity is combined with hot air temperature.

The National Weather Service wind chill equation is defined for air temperatures at or below 50 deg F and wind speeds above 3 mph.

Use heat index for hot and humid conditions, especially when air temperature is 80 deg F or higher. It is a shade-based estimate, so direct sun can make conditions feel hotter.

No. Wind chill describes heat loss from people and animals. Objects can cool faster in wind, but they do not become colder than the actual air temperature.

Some weather conditions are outside both formula ranges. In that case, the calculator reports actual air temperature and explains why wind chill or heat index is not active.