Solar forecasting app
Advanced Physical Engine. Enter your panel parameters — azimuth, tilt, peak power — and get precision forecasts powered by weather models and physics. Works with any installation, any brand.
Features
Works with any installation, any brand. Just enter your system parameters and let physics do the work.
Hourly and daily PV production forecasts using a full irradiance model, spectral corrections, and real weather data from multiple numerical forecast models. No hardware connection needed.
Log your actual production and the Kalman filter learns your system over time. The more data points, the more precise the predictions become.
An evening forecast for tomorrow, a snow warning when your panels may be covered, and a heads-up when it is the best time to run heavy appliances. Never miss a sunny window.
Glanceable widgets for Android and iOS showing today's forecast, tomorrow's outlook, and a multi-day overview — without opening the app.
How it works
Just describe your panels — azimuth, tilt, peak power — and start forecasting.
Azimuth, tilt angle, peak power, multi-string setup, bifacial factor, and horizon shading profile. That's all we need.
Volcast combines weather data from multiple forecast models with the physical model of your system to predict hourly and daily production.
Log actual production and the model auto-calibrates. Set up notifications and widgets to stay ahead.
Install the official HACS integration for the best experience — Energy Dashboard, live power sensor, peak production alerts, and automatic updates. Or use the REST API directly for custom setups.
Generate your API key in the Volcast app (Premium). No hardware access, no cloud polling — the data comes directly from the Volcast engine.
Included sensors
# Single API call returns daily + hourly + 5-min data curl -H "X-API-Key: vk_your_api_key" \ "https://volcast.app/api/forecast"
{
"state": 12.4,
"unit_of_measurement": "kWh",
"attributes": {
"forecast": {
"2026-03-17": { "energy_kwh": 12.4, "peak_w": 3200 },
"2026-03-18": { "energy_kwh": 8.1, "peak_w": 2800 }
},
"hourly": { /* 24 hourly entries per day */ },
"detailed": { /* 288 five-minute entries per day */ },
"api_version": 2
}
}
No analytics, no telemetry, no behavioral profiling. Your usage data stays on your device.
No banners, no interstitials, no sponsored content. Ever.
Volcast never connects to your inverter or any hardware. All forecasts are computed from weather model data and your panel parameters.
Get Volcast
Available on Android and iOS. Download free and start forecasting.
FAQ