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Energy Review
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7-day solar generation forecast for the UK

Estimate how much electricity your solar panels could generate over the next seven days. Start with your UK postcode and your best-ever solar day.

Your postcode is sent once to Postcodes.io to find approximate coordinates. It is not put in the URL, analytics or database. Forecast history and any actual readings you add stay in this browser under a one-way postcode key. This version covers England, Scotland and Wales.

How we calculate your solar forecast

The forecast starts with hourly solar irradiance rather than cloud cover alone. Irradiance measures the solar energy expected to reach a horizontal surface in your area. We compare that forecast with the conditions expected on a very good solar day at your latitude, including the changing length and height of the solar day through the seasons.

Your best-ever daily generation then calibrates that solar potential to your real installation. The estimate is capped close to your observed best rather than assuming an unusually bright forecast can make the system produce without limit. After the first result, you can optionally add system size, roof direction, pitch and annual generation. Those details refine the hourly shape and contribute a bounded physical estimate, while your observed best day remains the anchor. Shading is still not known, so the figures should be read as likely generation, not a promise.

What can move the result

Cloud that forms more locally than the weather model can resolve
Shade from trees, chimneys or nearby buildings
East-, west- or split-facing panel arrays
Snow, dirt, panel temperature and inverter clipping

Plan the rest of your solar setup

Still deciding whether to install panels? Check a specific property with our UK solar roof calculator, or start with a quicker solar panel cost and payback estimate. If you already export surplus electricity, the solar battery calculator models how much of it a battery could move into household use.

Frequently asked questions

How does the solar generation forecast work?

Energy Review uses forecast hourly solar irradiance for your postcode area and compares it with a clear-sky reference for the same latitude. Your best-ever daily generation calibrates that solar potential to the real performance of your own installation.

Is the forecast guaranteed?

No. It is an estimate. Local cloud, shading, snow, dirt, inverter clipping and panel direction can all make actual generation differ from the forecast, especially further into the seven-day period.

Why do you ask for my best solar day?

It provides a low-friction measurement of how your complete system performs, including its panels, inverter and installation. You can usually find the highest daily generation in your inverter or energy app.

Do you store my postcode?

No. The postcode is sent to Postcodes.io to obtain approximate coordinates for the forecast. Energy Review does not put it in the page URL, analytics or database.

Does the forecast cover Northern Ireland?

Not in this first version. It covers England, Scotland and Wales because Northern Ireland postcode data has separate commercial licensing requirements.

Can I get a solar forecast using only my postcode?

Yes. A postcode and your best-ever daily generation are enough for the first result. Your system size, roof direction, pitch and annual generation are optional refinements.