Solar panel generation forecast
Enter your panels, the way your roof faces and its tilt to see what they are likely to generate today and over the next three days. For sunshine hours, temperature and wind, see the local solar and weather forecast.
Your panels
4 kWp in totalMost pitched roofs are 30° to 45°.
An estimate, not measured generation: it assumes no shading and 15% system losses, and uses the forecast cloud cover, so real output will vary. Weather data from MET Norway, licensed under CC BY 4.0. Place search by postcodes.io. Contains OS data © Crown copyright and database right, Royal Mail data © Royal Mail copyright and database right, and ONS data licensed under the Open Government Licence.
Have a home battery? Where your setup is supported, verified and customer-enabled, 1app.energy can use a solar forecast like this to decide how much to charge it overnight.
Common questions about solar panel generation
How do I use it?
Search your town or postcode, then fill in each roof: how many panels, the watts of each panel, which way they face and their tilt. Use Add another roof for panels facing a different way, and tap a day to see it hour by hour. It is free, needs no account, and remembers your place and panels only in your browser.
Where do I find my panel details?
The watts per panel are on your installer's paperwork or the label on the panel. Most panels fitted in recent years are 350 to 450 W. If you only know the system size in kWp, divide it by the number of panels and multiply by 1,000 to get the watts.
How is the generation estimate worked out?
We take MET Norway's cloud cover forecast for your area and the sun's position for each hour, then work out how much sunlight reaches panels of your size, direction and tilt. We take off 15% for system losses and assume no shading. It is an estimate, not a reading from your inverter.
How much do solar panels generate in the UK?
Over a year, a typical UK system makes about 850 kWh for each kWp of panels, more in the south and less in the north. On a clear summer day, panels facing south make about 7 kWh per kWp. On a clear December day, it is nearer 2 kWh per kWp.
Do east and west facing panels make less than south facing ones?
A little less over the day, but they spread it out: east panels make more in the morning and west panels more later in the afternoon. Add each roof separately to see the combined output hour by hour.
What tilt should I enter?
Most pitched roofs in the UK are between 30° and 45°. If you are not sure, 35° is a good starting point. Choose Flat for panels lying flat.
Why might my panels make a different amount?
Shading from trees or buildings, haze, dirt, older panels and an inverter that caps output can all lower it, and cloud forecasts change. Use the estimate as a guide to the best days and hours, not a promise.
How far ahead does the forecast go?
The rest of today from the current hour, then the next three days. MET Norway updates its forecast about every hour, and the time of the last update is shown above the estimate.
How does this help with a home battery?
If tomorrow looks sunny, a battery may need less cheap overnight charge. If it looks dull, it may need more. Where your setup is supported, verified and customer-enabled, 1app.energy can make that choice for you from your own solar forecast and tariff.