A solar array in Wembley does not make the same amount of electricity in every month, and the gap between summer and winter is wider than most people expect. In June a south-facing roof in HA0 or HA9 makes more than most households can use in daylight; in December the same roof makes about a third as much. That swing, not the annual total, is what should shape how many panels you fit and whether a battery makes sense. For what an installation involves locally, see our page on solar panels in Wembley.
The figures below come from PVGIS 5.3, the European Commission’s solar model, run for a point in central Wembley: 4 kWp of panels facing due south at 35°, building-mounted, with 14% system losses, on the PVGIS-SARAH3 satellite record for 2005–2023. It gives about 3,963 kWh a year, or 991 kWh per kWp, with a typical year-to-year swing of around ±150 kWh. That is the best case for an unshaded roof.
Month by month on a Wembley roof
| Month | PVGIS output, 4 kWp (kWh) | Per day (our arithmetic) |
|---|---|---|
| January | 159 | 5.1 |
| March | 339 | 10.9 |
| May | 468 | 15.1 |
| June | 476 | 15.9 |
| July | 480 | 15.5 |
| September | 369 | 12.3 |
| November | 186 | 6.2 |
| December | 141 | 4.5 |
April to September together produce about 2,663 kWh, roughly two-thirds of the year. November to February produce about 695 kWh, under a fifth (our arithmetic). December’s output is about 30% of June’s.
The light behind those numbers is well recorded. The two Met Office stations nearest central Wembley with a sunshine record sit about five miles away in opposite directions. Kew Gardens, to the south, averaged 1,693 hours a year over 1991–2020, with about 222 in July and about 53 in December; Hampstead, to the east, averaged 1,559. Both are above the UK average of 1,403 hours.
Set against what a household uses
Ofgem’s typical domestic consumption value from 1 July 2026 is 2,500 kWh a year, which averages about 208 kWh a month or 6.8 kWh a day. On a monthly basis, the Wembley array makes more than that from March to October, is roughly level in February and falls short in November, December and January (our arithmetic). A monthly balance flatters solar, though, because generation peaks around midday and use peaks in the evening. Even in June, much of a Wembley roof’s output is exported unless someone is home or a battery stores it.
What the swing means for how many panels
It is tempting to size an array to cover winter. On these figures that does not work. Doubling a Wembley array from 4 kWp to 8 kWp would lift December from about 141 to about 282 kWh, enough on paper for an average month but made mostly around midday on short days, while pushing June to roughly 950 kWh, far more than a typical house can use or store (our arithmetic). The better guide is the roof itself and your annual use. The Energy Saving Trust describes a typical domestic system as around 4.5 kWp, about 12 panels over 20 to 30 m² of roof. Our guide to whether solar panels work on cloudy days explains why the winter figure is low but not zero.
Which slope you are allowed to use
Wembley adds a local wrinkle. Brent says all of its residential conservation areas are covered by Article 4 directions, and the Barn Hill and Wembley High Street directions, in force since 18 December 2021, withdraw the permitted development right for solar on houses within their mapped areas except on rear roof slopes. On those streets the rear slope’s orientation, not the best slope, sets the seasonal curve. A rear slope facing east or west makes less than the due-south figures above, and loses most in winter, when the sun is low in the southern sky.
Where a battery fits in the year
A battery’s job is to move a daytime surplus into the evening. On a Wembley roof that surplus is large from roughly April to September and small to absent from November to January. That is why a battery is sized to your summer evenings, not to winter: a battery big enough for every June surplus sits part-empty for months. Our page on battery storage in Wembley covers sizing and siting, and our guide to battery storage without solar panels covers charging from the grid on a cheaper overnight rate in winter, which is a tariff question, not a solar one.
Homes without a roof of their own
In Wembley Park, 98.2% of households lived in purpose-built flats at the 2021 Census, so for most residents there the seasonal curve belongs to a freeholder’s roof. In Wembley Central and Wembley Hill, 28.1% of households live in semis, and those are the roofs where these figures most often apply directly.
Getting a figure for your own roof
Everything here is modelled for an unshaded, due-south Wembley roof. Your own figures depend on direction, pitch and shade, which a survey measures. Wembley is part of our solar panels in North London coverage. If your roof’s seasonal curve would not justify panels, we will say so. You can ask for a survey through our contact page.
Sources: PVGIS 5.3, European Commission Joint Research Centre (PVGIS-SARAH3 2005–2023; 4 kWp, 35°, due south, 14% losses, building-mounted; central Wembley run 15 October 2026, monthly figures re-checked 18 October 2026); Met Office, Kew Gardens and Hampstead location-specific long-term averages 1991–2020; Ofgem, typical domestic consumption values from 1 July 2026; Energy Saving Trust, Solar panels: costs, savings and benefits explained (updated 27 August 2026); London Borough of Brent, Article 4 directions for Barn Hill and Wembley High Street conservation areas and Listed buildings and conservation areas page; ONS Census 2021, TS044, Wembley Park, Wembley Central and Wembley Hill wards, via Nomis. Daily, seasonal and scaled figures are our arithmetic.