UK solar forecasting

Know how much solar you’re likely to make — and when.

Enter your postcode and panel setup for an hourly generation forecast. No account is needed to try it.

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Great Britain solar now0 MW·0.0%of ~27.1 GW estimated demandPV_Live + Elexon· It’s too dark for meaningful solar generation across Great Britain at the moment.

Checking Great Britain solar now…

Your installation

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UK postcode

What is kWp?

kWp is the total rated power of your solar panels. If you think of your system as “4 kW of solar”, that is usually entered as 4 kWp here. If you do not know the kWp figure, choose I know my panels and enter how many panels you have and the wattage printed on each panel. Your inverter rating can be different from your panel capacity.

Array name

How much solar is in this array?

Total size (kW / kWp)

If you know it as a “4 kW solar system”, or your quote says 4 kWp of panels, enter 4. If 4 kW is only your inverter rating, use the panel option instead.Use one array for panels that face the same direction and have roughly the same tilt.

DirectionNot sure? The sun rises in the east, is highest in the south, and sets in the west. Choose the direction the panels face when you look outward from the roof.

Panel tilt

Custom tilt (°)

0° is flat; 90° is a vertical wall.

Advanced settings (optional)

System efficiencyNot sure? Leave this on Recommended. We deliberately start a little cautious for wiring, mismatch, dirt, shading and other real-world losses. Normal inverter conversion is allowed for separately, and saved installations can learn from your actual generation.

Inverter AC limit (kW)

Only set this if you know the maximum AC output of your inverter.

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0.000 kWp configured

Multiple arrays

Model different roof faces, tilts and panel capacities separately.

Useful timing

See expected kWh, peak output and the strongest generation window.

Gets personal

Save your system and add real generation totals. Solar Forecast can learn how your installation performs and gently tune future forecasts to match it.

Know when plans change

Choose email or push updates and your own high/low generation thresholds, so you can act when tomorrow looks better — or worse — than expected.

Free to use — no strings attached. No ads. We do not and will not sell your data.Public forecasts are not saved. Saved installations retain a postcode district and rounded forecast coordinates, not the full postcode.

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