A library of atmospheric and weather-related calculations.
- Includes test code for all formulas.
- Supports custom valuation sets where applicable.
- Supports both ES Module (ESM) and CommonJS (CJS).
- Dew Point: Calculate the dew point using the Magnus formula or Arden Buck equation.
- Wind Chill: Estimate the perceived temperature based on wind speed and air temperature.
- (Australian) Apparent Temperature: Calculate the apparent temperature considering humidity and wind.
- Heat Index: Measure the perceived temperature based on air temperature and humidity.
- Humidex: Calculate the humidex, a Canadian measure of perceived temperature.
- Potential Temperature: Calculate the temperature an air parcel would have if brought to a standard pressure.
- Virtual Temperature: Calculate the temperature accounting for water vapor in the air.
- Lapse Rate: Calculate the rate of temperature change with altitude.
- Dynamic lapse rate: Calculate the lapse rate dynamically based on readings.
- Weighted Average Temperature: Calculate the weighted average temperature based on altitude differences.
- Adjust Temperature by Lapse Rate: Adjust temperature based on a fixed lapse rate.
- Relative Humidity: Calculate the ratio of the current absolute humidity to the maximum possible humidity.
- Specific Humidity: Calculate the mass of water vapor per unit mass of air.
- Mixing Ratio: Calculate the ratio of water vapor to dry air.
- Vapor Pressure: Calculate the partial pressure of water vapor in the air.
- Saturation Vapor Pressure: Calculate the maximum vapor pressure at a given temperature.
- Pressure Altitude: Calculate the altitude based on observed pressure.
- Density Altitude: Calculate the altitude adjusted for temperature and air density.
- Barometric Formula: Calculate pressure at a given altitude using the barometric formula.
- Adjust Pressure To Sea Level:
- Simple formula: A quick approximation for standard conditions.
- Advanced formula: A more accurate calculation using the barometric formula.
- By dynamic lapse rate: Adjust pressure using a dynamically calculated lapse rate.
- By historical data: Adjust pressure using historical readings.
Install the library using npm:
$ npm install weather-formulasIf your project is configured to use ES Modules (e.g., "type": "module" in package.json), you can use the import syntax to load the package:
import { temperature, humidity, pressure } from 'weather-formulas';
// Example usage
const RH = humidity.relativeHumidity(298.15, 293.15); // 25°C and 20°C in Kelvin
console.log(`Relative Humidity: ${RH}%`);If your project uses CommonJS (e.g., no "type": "module" in package.json), you can use the require syntax to load the package:
const { temperature, humidity, pressure } = require('weather-formulas');
// Example usage
const RH = humidity.relativeHumidity(298.15, 293.15); // 25°C and 20°C in Kelvin
console.log(`Relative Humidity: ${RH}%`);Use a provided valuation set:
const valuationSet = temperature.DEW_POINT_VALUATIONS.DAVID_BOLTON;
const actual = temperature.dewPointMagnusFormula(298.15, 60, valuationSet); // 25°C and 60% humidity
console.log(`Dew Point: ${actual} K`);Use a custom valuation set:
const valuationSet = { a: 6, b: 17, c: 250, d: 234.5 };
const actual = temperature.dewPointArdenBuckEquation(298.15, 60, valuationSet); // 25°C and 60% humidity
console.log(`Dew Point: ${actual} K`);Inspect code/tests for all possibilities.
Please feel free to contribute by creating a Pull Request including test code, or by suggesting other formulas.
This project is licensed under the GPL v3 License.
For support, please open an issue in the GitHub repository.
Always verify calculations before using in production as edge cases due to floating point errors may exist for large numbers, and which may not be covered by tests today. Please report any issues.