How much will solar panels produce in Castlebar?

A 4 kWp system facing south at 35° tilt in Castlebar produces about 3,518 kWh a year. In a weak year that is 2,944 kWh, in a good one 4,093 kWh — 880 kWh per kWp.

That’s about 84% of a typical home’s yearly use (4,200 kWh).

Calculate for my roof

Based on 2014–2023 satellite weather data

Production by month

0200400600800JanJanuary: 4 kWp 104 kWh, range 80–129FebFebruary: 4 kWp 171 kWh, range 133–210MarMarch: 4 kWp 307 kWh, range 244–370AprApril: 4 kWp 418 kWh, range 319–517MayMay: 4 kWp 511 kWh, range 419–602JunJune: 4 kWp 436 kWh, range 344–528JulJuly: 4 kWp 433 kWh, range 356–510AugAugust: 4 kWp 411 kWh, range 340–482SepSeptember: 4 kWp 311 kWh, range 255–366OctOctober: 4 kWp 222 kWh, range 169–276NovNovember: 4 kWp 130 kWh, range 100–160DecDecember: 4 kWp 85 kWh, range 65–105

kWh per month

A typical day in May

The sunniest month in Castlebar. Output peaks around 11:00 solar time, at about 1.7 kWh in the best hour.

0:006:0012:0018:0023:00 1.7 0

Month by month

Month Weak year, kWh Typical year, kWh Good year, kWh
January 80 104 129
February 133 171 210
March 244 307 370
April 319 418 517
May 419 511 602
June 344 436 528
July 356 433 510
August 340 411 482
September 255 311 366
October 169 222 276
November 100 130 160
December 65 85 105
Year 2,944 3,518 4,093

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 Castlebar?

From November to February the system produces about 491 kWh, which is 14% of the year. The weakest month (December) gives roughly 85 kWh.

Is an east-west roof worth it in Castlebar?

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 Castlebar

Ground mount or roof in Castlebar?

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 Castlebar

Your roof is not an average roof

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

Calculate for my roof

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