How much will solar panels produce in Cardiff?

A 4 kWp system facing south at 35° tilt in Cardiff produces about 4,311 kWh a year. In a weak year that is 3,591 kWh, in a good one 5,031 kWh — 1,078 kWh per kWp.

That’s about 160% of a typical home’s yearly use (2,700 kWh).

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Based on 2014–2023 satellite weather data

Production by month

0200400600800JanJanuary: 4 kWp 136 kWh, range 106–166FebFebruary: 4 kWp 222 kWh, range 173–270MarMarch: 4 kWp 371 kWh, range 286–456AprApril: 4 kWp 485 kWh, range 382–589MayMay: 4 kWp 544 kWh, range 432–656JunJune: 4 kWp 541 kWh, range 423–658JulJuly: 4 kWp 545 kWh, range 443–648AugAugust: 4 kWp 481 kWh, range 393–570SepSeptember: 4 kWp 384 kWh, range 307–461OctOctober: 4 kWp 262 kWh, range 208–316NovNovember: 4 kWp 172 kWh, range 138–207DecDecember: 4 kWp 114 kWh, range 76–152

kWh per month

A typical day in July

The sunniest month in Cardiff. Output peaks around 11:00 solar time, at about 2.2 kWh in the best hour.

0:006:0012:0018:0023:00 2.2 0

Month by month

Month Weak year, kWh Typical year, kWh Good year, kWh
January 106 136 166
February 173 222 270
March 286 371 456
April 382 485 589
May 432 544 656
June 423 541 658
July 443 545 648
August 393 481 570
September 307 384 461
October 208 262 316
November 138 172 207
December 76 114 152
Year 3,591 4,311 5,031

The months don’t add up exactly to the yearly figure, because each one is the typical value across many years.

Common questions

How much do solar panels produce in winter in Cardiff?

From November to February the system produces about 644 kWh, which is 15% of the year. The weakest month (December) gives roughly 114 kWh.

Is an east-west roof worth it in Cardiff?

An east-west system typically produces 10–25% less per kWp than one facing south, but spreads production more evenly through the day. The exact difference depends on tilt and shading.

Compare an east-west roof for Cardiff

Ground mount or roof in Cardiff?

A ground mount can be tilted and aimed freely, which can add some yield, but it costs more and needs space. Compare both for your own plot.

Check a ground-mounted system in Cardiff

Your roof is not an average roof

Set your own tilt, direction, shading and inverter limit and get a range for your address.

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Climate data: Photovoltaic Geographical Information System (PVGIS) — European Commission, Joint Research Centre