Hi everyone,
Most of us feed a local weather station (Ecowitt, WeatherFlow, Davis, Ambient, Netatmo, Shelly, and others) into Home Assistant. The catch is that raw station data is reactive: it tells you the temperature and rain rate right now, but not what is about to happen. For real automations you need the next step. When will it rain, how much water does the lawn actually need, is a freeze coming tonight.
That is what Weather Station Core (ws_core) does. You give it 7 base sensors (temperature, humidity, pressure, wind speed, gust, direction, rain) and it derives 150+ meteorological entities, calculated locally. No API keys are required for the core features.
What makes it different
Ground-truth nowcasting. ws_core blends your physical rain gauge with the Open-Meteo 15-minute grid. If your gauge detects rain before the forecast expected it, the integration shifts its prediction immediately, so sensor.ws_minutes_until_rain reflects what is actually falling in your garden, not just what a model expected.
It still works offline. If your internet drops, the smart home keeps forecasting. A Zambretti pressure-trend forecaster uses your local barometric data to produce a 12-hour outlook and the classic 26-condition classification, with no external dependency.
Built for automations, not just dashboards. It ships the indices you actually trigger on:
- Evapotranspiration (ET0) for precise irrigation
- UTCI (Universal Thermal Climate Index) for heat-stress logic
- Fire danger via the Canadian FWI and Australian FFDI
- A fog probability estimate, plus dew point, frost point, wind chill, and cloud base
Setup is genuinely quick
If your station is already in Home Assistant, ws_core auto-discovers your sensors during the config flow. For the common integrations (Ecowitt, WeatherFlow Tempest, Netatmo, Ambient) you usually just confirm the mapping and you are done.
Blueprints included
Ten importable blueprints to get automations running immediately:
- Rain Start Warning
- Heat Stress / UTCI Alert
- High Wind / Gusts
- Poor Air Quality
- Fire Danger Alert
- Frost & Freeze Alert
- Irrigation Rain Skip
- Lightning Safety
- Storm Alert (pressure drop)
Dashboards included
The repo ships drop-in YAML for detailed mobile and desktop dashboards, so you can see everything at a glance.
Install (HACS custom repository)
It is available now as a HACS custom repository, and I have submitted it for inclusion in the default HACS store.
- HACS > Integrations > 3 dots > Custom repositories
- Add
https://github.com/kmich/ha_ws_core(Category: Integration) - Install, restart, then go to Settings > Devices & Services to set it up
If you want the math behind every derived sensor, the Science Docs cover each formula and its references.
I would love feedback, especially edge cases with less common stations, and I am taking feature requests.