Financial calculator category
Weather calculators
Weather calculators: Calculate wind chill, heat index and dew point using the official National Weather Service formulas. The category holds 5 tools, including the Wind Chill Calculator, the Heat Index Calculator and the Dew Point Calculator.
Wind Chill combines temperature and wind speed into a cold feel, and Heat Index combines temperature and humidity into a hot feel. Dew Point measures the moisture in the air and predicts fog and frost. Heating & Cooling Degree Days total how much heating or cooling a location needed, and Snow-to-Liquid Ratio converts snowfall to water content. Use the first three for safety and comfort, and the last two for energy and hydrology. Check the forecast source.
Among the tools here are Wind Chill Calculator, Heat Index Calculator, Dew Point Calculator, Heating & Cooling Degree Days Calculator, Snow-to-Liquid Ratio Calculator.
Pick one below. Open it.
Wind Chill Calculator
Calculate the wind chill "feels-like" temperature using the official NWS formula.
Open calculator →02Heat Index Calculator
Calculate the heat index "feels-like" temperature from air temperature and humidity.
Open calculator →03Dew Point Calculator
Calculate dew point and the temperature-dew point spread from temperature and humidity.
Open calculator →04Heating & Cooling Degree Days Calculator
Calculate heating and cooling degree days from an average daily temperature using the standard 65°F base.
Open calculator →05Snow-to-Liquid Ratio Calculator
Estimate snowfall from liquid precipitation using an entered snow-to-liquid ratio.
Open calculator →Every tool, one table
Weather calculators at a glance
Each row shows the headline figure that calculator returns at its own worked-example inputs.
| Calculator | What it answers | Headline output | Worked example |
|---|---|---|---|
| Wind Chill Calculator | The formula is validated only at or below 50°F with wind at or above 3 mph. | Feels-like temperature (°F) | 6.2 |
| Heat Index Calculator | Heat index is calculated for shaded conditions; direct sun can add significantly more. | Feels-like temperature (°F) | 113.1 |
| Dew Point Calculator | A smaller spread signals more humid, muggier conditions regardless of the raw temperature. | Dew point (°F) | 57.7 |
| Heating & Cooling Degree Days Calculator | Degree days estimate relative energy demand, not an actual utility bill. | Heating degree days | 10 |
| Snow-to-Liquid Ratio Calculator | Adjust the ratio for actual air temperature; the real ratio varies well outside the commonly cited 10:1 average. | Estimated snowfall (inches) | 5 |
Where people go wrong with weather numbers
Wind chill and heat index are defined only within certain ranges: wind chill applies at or below 50 degrees Fahrenheit and the heat index at or above 80. They also assume conditions such as shade for the heat index, and direct sun can raise the felt temperature by 15 degrees. Neither changes the actual air temperature, which matters for freezing pipes. Snow-to-liquid ratios vary a lot between wet and dry snow. Feels-like is not actual. Pipes freeze at real temperature.
Definitions
Weather terms
- Dew point : glossary term
- The temperature air would need to cool to for it to become fully saturated with the moisture it currently holds. A higher dew point means more humid, muggier air.
- Heat index : glossary term
- A calculated "feels-like" temperature that combines air temperature and relative humidity to estimate how hot the body actually perceives conditions to be.
Keep exploring
Related calculator categories
Next to the weather tools, these categories answer the questions that usually come up alongside them.
Common weather questions
Why do wind chill and heat index use different temperature ranges?
Wind chill models how quickly the body loses heat, which only matters meaningfully in cold conditions with real wind: its official range is 50°F and below with wind at 3 mph or higher. Heat index models how heat and humidity together strain the body's cooling, which is a distinct warm-weather phenomenon.
Is heat index the same as "real feel" temperature on a weather app?
It's usually the primary input. But some apps blend in additional factors like sun exposure or wind. The heat index alone assumes shaded conditions: direct sunlight can add significantly to how hot it actually feels beyond the calculated value.
Why does a smaller temperature-dew point spread mean more humidity?
Dew point tracks the actual moisture content of the air , not how it feels relative to temperature. When dew point sits close to the air temperature, the air is nearly saturated with moisture, which is what produces that heavy, muggy feeling regardless of the thermometer reading.
Can wind chill or heat index go below/above the actual temperature by a huge margin?
Yes, especially at extreme wind speeds or humidity levels, but the further outside the formula's documented valid range you go, the less physically meaningful the number becomes. Treat results near or outside the documented boundaries as illustrative instead of precise.
Why do these calculators use Fahrenheit instead of Celsius?
Both the official NWS wind chill and heat index formulas were derived and published in Fahrenheit, so using them directly in Fahrenheit avoids an extra conversion step that could introduce rounding differences from the source formulas.
People also ask
Weather calculator questions
What is a dangerous heat index?
The National Weather Service treats a heat index of 103 to 124 degrees Fahrenheit as dangerous, and above 125 as extremely dangerous.
What does the dew point tell me?
It is the temperature at which the air becomes saturated, and a dew point above about 65 degrees Fahrenheit feels muggy.
Does wind chill change the real temperature?
No. It describes how fast exposed skin loses heat, while objects such as pipes cool only to the actual air temperature.