#dew-point

Moist-air (psychrometric) thermodynamics as an API, computed locally and deterministically. The dewpoint endpoint computes the dew-point temperature and the saturation and actual water-vapour pressures from a dry-bulb temperature and relative humidity, using the Magnus-Tetens relation over water, es = 6.112·exp(17.62·T/(243.12+T)) hPa — the dew point is the temperature to which air must cool for water vapour to start condensing. The humidity-ratio endpoint computes the humidity ratio (mixing ratio) W = 0.621945·Pw/(P−Pw), the specific and absolute humidity, the vapour pressure and the moist-air enthalpy h = 1.006·T + W·(2501 + 1.86·T) kJ per kg of dry air, at any total pressure (default sea-level 101325 Pa). The wet-bulb endpoint computes the wet-bulb temperature with the Stull (2011) empirical fit and the wet-bulb depression, the gap between dry- and wet-bulb that widens as the air gets drier. Temperatures are in °C, relative humidity in %, pressures in Pa. Everything is computed locally and deterministically, so it is instant and private. Ideal for HVAC, building-physics, meteorology, drying, greenhouse and data-centre-cooling app developers, comfort and condensation-risk tools, and engineering education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is moist-air psychrometrics; for ASHRAE ventilation airflow use a ventilation API, for the WBGT heat-stress index a WBGT API and for the standard atmosphere an atmosphere API.

api.oanor.com/psychrometric-api

Meteorological formulas as an API — the derived weather figures, computed from your own readings, with no data feed or key needed. The wind-chill endpoint gives the "feels like" cold using the Environment Canada formula in metric (°C, km/h) or the US NWS formula in imperial (°F, mph), and flags when the reading is outside the valid range. The heat-index endpoint gives the apparent temperature from heat and humidity using the NWS Rothfusz regression with the standard low- and high-humidity adjustments. The dew-point endpoint uses the Magnus formula to turn temperature and relative humidity into the dew point, and also returns the vapour pressure and the absolute humidity. The beaufort endpoint maps a wind speed (m/s, km/h, mph or knots) to its Beaufort force and description, or a force back to its speed range. Everything is computed locally and deterministically, so it is instant and private. Ideal for weather apps and dashboards, agriculture and HVAC, marine and aviation, and outdoor and safety tools. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 5 endpoints. This computes weather formulas from your own readings; for live forecasts and observations use a weather data API.

api.oanor.com/weathercalc-api