Weather & Environment calculators (9)

Heat index, wind chill, dew point, relative humidity, air density, pressure altitude, boiling point at altitude, carbon footprint of driving and electricity.

Markdown version: /weather.md · JSON: /api/v1/calculators?category=weather

• Heat Index Calculator — Computes the NWS heat index ('feels like' temperature in the shade) from air temperature and relative humidity with the Rothfusz regression, including the NWS low- and high-humidity adjustments, and classifies the NWS risk category. (md · api)
• Wind Chill Calculator — Computes the wind chill temperature from air temperature and wind speed with the 2001 JAG/TI formula used by the US National Weather Service and Environment Canada, and reports the frostbite risk band for exposed skin. (md · api)
• Dew Point Calculator — Computes the dew point temperature from air temperature and relative humidity with the Magnus formula (Alduchov & Eskridge coefficients a = 17.625, b = 243.04 °C), plus vapour pressures and a comfort classification. (md · api)
• Relative Humidity Calculator — Computes relative humidity from air temperature and dew point as the ratio of Magnus-formula vapour pressures, and the absolute humidity (grams of water vapour per cubic metre) from the ideal-gas law for water vapour. (md · api)
• Air Density Calculator — Computes the density of humid air from temperature, station pressure and relative humidity as a mixture of ideal gases (dry air plus water vapour, vapour pressure from the Magnus formula), and the ISA density altitude. (md · api)
• Pressure Altitude Calculator — Converts between pressure and altitude in the ICAO International Standard Atmosphere: pressure altitude from station pressure (or from QNH/altimeter setting plus field elevation), and the ISA pressure and temperature at a given altitude. (md · api)
• Boiling Point at Altitude Calculator — Computes the boiling point of water at a given altitude by taking the ISA pressure at that altitude (or a measured station pressure) and solving the Antoine equation for water, with a note on cooking at altitude. (md · api)
• Driving Carbon Footprint Calculator — Estimates tailpipe CO₂ (and CO₂-equivalent including methane and nitrous oxide) for a car trip from distance and fuel economy or fuel used, using per-litre combustion factors for petrol, diesel and LPG, and scales to a yearly total. (md · api)
• Electricity Carbon Footprint Calculator — Multiplies electricity consumption by a regional grid emission factor (world, US, Australia, EU, China, India or a custom value, kg CO₂ per kWh) to estimate monthly and yearly CO₂, and expresses the yearly total as mature-tree absorption years. (md · api)