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Weather Calculators & Tools

Every free calculator on Tornado Hub in one place. No sign-up, no ads-to-unlock — just working tools built on real formulas and NOAA data.

Tornado Risk Calculator

Your odds of death, injury, or property damage this year, decade, and lifetime, by state and home type.

Days Until Tornado Season

Live countdown to peak severe-weather season for your region, from the Plains to Canada.

Heat Index Calculator

What the temperature really feels like once humidity is factored in, with danger categories.

Wind Chill Calculator

Feels-like temperature and how fast exposed skin can freeze, using the official NWS formula.

UV Index Calculator

How long until you sunburn, by skin type and SPF, at today's UV index.

Humidity Calculator

Convert between relative humidity, dew point, and absolute humidity, with a comfort rating.

Dew Point Calculator

Find the dew point from temperature and humidity, the honest measure of how muggy it feels.

Snow Day Calculator

Estimate the chance school is cancelled tomorrow from snowfall, timing, and where you live.

Wind Speed Converter

Convert mph, km/h, knots, m/s, and the Beaufort and EF scales in one place.

Pressure Converter

Convert millibars, inHg, hPa, kPa, mmHg, and psi, with tornado and hurricane context.

Built to actually work

These are not novelty widgets. The heat index uses the official National Weather Service Rothfusz regression, wind chill uses the 2001 NWS standard, and the humidity and dew point tools use the Magnus-Tetens equations meteorologists rely on. Where a tool is an estimate rather than an exact figure — like the snow day and sunburn calculators — the page says so plainly.

More to explore

When you are done crunching numbers, test your eye with the weather trivia quizzes, play the daily Tornadle, or look up the tornado history where you live.