Weather & Atmosphere Calculators
Understand what the weather really feels like — calculate the heat index, wind chill and "feels like" temperature, work out the dew point and humidity, gauge dangerous wet-bulb heat, read the Beaufort wind scale and estimate cloud base. Official meteorological formulas, running entirely in your browser.
- Heat Index Calculator Enter the temperature and humidity to get the heat index
- Wind Chill Calculator Enter the temperature and wind speed to get the wind chill
- Dew Point Calculator Enter the temperature and humidity to get the dew point
- Relative Humidity Calculator Enter the air temperature and dew point to get the relative humidity as a percentage.
- Feels Like Temperature Calculator Enter the temperature, humidity and wind speed to get the apparent "feels like" temperature.
- Wet Bulb Temperature Calculator Enter the temperature and humidity to get the wet-bulb temperature
- Beaufort Wind Scale Calculator Enter a wind speed in any unit to get its Beaufort force number, name and the effects you'd see.
- Cloud Base Calculator Enter the surface temperature and dew point to estimate the height of the cloud base above ground.
- Absolute Humidity Calculator Enter the air temperature and relative humidity to get the absolute humidity: the real amount of water vapour in the air, in grams per cubic metre.
- VPD Calculator (Vapor Pressure Deficit) Enter air temperature, relative humidity and an optional leaf-temperature offset to get the VPD in kPa
- Rainwater Collection Calculator Enter your roof's footprint area, the rainfall and a runoff coefficient to see how much water you can collect, in litres and US gallons.
- Density Altitude Calculator Enter your field elevation, altimeter setting and outside air temperature to get the pressure altitude and density altitude.
- Snow Load Calculator (Roof) Enter the snow depth and choose
- Humidex Calculator Enter the air temperature and dew point to get the humidex and how it feels.
- Sea-Level Pressure Calculator Enter your barometer's station pressure, your altitude and the temperature to get the equivalent sea-level pressure.
Frequently asked questions
Are these weather calculators accurate?
They use the official meteorological formulas — the NWS Rothfusz heat index, the 2001 NWS wind chill, the Magnus dew-point equation and Stull's wet-bulb formula, each cited on its tool page. They compute an index from the values you enter; they don't fetch live weather.
Do they work in °C and °F?
Yes — every temperature tool toggles between Fahrenheit and Celsius (and wind speed between mph and km/h), converting internally.
Do these show a live forecast?
No — they're calculators. Enter the temperature, humidity or wind and they compute the heat index, dew point, wind chill and so on. For a live forecast or official warnings, use your national weather service.
Is my data uploaded?
No. Every tool runs entirely in your browser — nothing is sent to a server, and they work offline.