Sunplan: Solar Forecast

Sunplan predicts how much energy your solar installation will produce — hour by hour, seven days ahead. This is not a weather app with a chart bolted on. Sunplan calculates output from a physical model: the sun's position for your exact coordinates, your roof geometry, and how forecast cloud cover attenuates solar radiation. HOW IT WORKS You enter your installation parameters: capacity, azimuth, tilt angle and location. Sunplan computes clear-sky irradiance, then corrects it for forecast cloud cover from Apple WeatherKit. The result is predicted production in kWh, for every hour and as a daily total. WHAT YOU GET - 3-day production forecast - Hourly breakdown with the daily production peak - Daily totals in kWh - Day-to-day comparison - Multiple installations, if you have more than one array WHO IT'S FOR For anyone running rooftop solar who wants to plan self-consumption. Know in advance which day is worth running the dishwasher, the washing machine or the EV charger — and when to charge your home battery from the grid instead. PRIVACY Sunplan has no server. Every calculation runs on your iPhone. No account, no email, no sign-in. Your installation parameters stay on the device. I collect nothing. No ads, no tracking. ABOUT ACCURACY A production forecast is only as good as the cloud forecast behind it. Next-day predictions are usually close. The further out the day, the wider the uncertainty — especially under broken cloud, when output swings minute to minute. Sunplan shows a prediction, not a promise. Treat it as a planning tool. WHAT SUNPLAN DOESN'T DO It doesn't connect to your inverter or read actual production. It doesn't control anything in your home. Nothing to install beyond the app. I built Sunplan because I run solar at home and wanted to know what to expect. I'm still developing it — if something's missing, write to me.