Every month, UrbanVolt publishes a solar generation update for our clients across the UK and Ireland, so you always know how the weather has affected your system’s output.
United Kingdom
October 2026 was mild, wet, and changeable, with relatively positive levels of irradiance.
The first two weeks were a run of frontal systems crossing the country with rain, sometimes heavy. There were settled spells in between, but none lasted more than a few days, so the weather kept flipping between dry and bright and wet and grey. The first snow of the season fell on the Scottish mountain tops on 7th October, and northern Scotland had strong winds and some severe gales around the 12th and 13th. Mid-month brought a cooler spell, with temperatures below average for much of the UK.
The second half of the month was dominated by the first two named storms of the 2026/27 season. Storm Austen was named on the 20th and deepened very quickly as it approached the south of the UK. It arrived on the 22nd with heavy rain and strong winds, and the Isles of Scilly recorded a gust of 76mph. Storm Boelo followed, named on the 22nd, and brought heavy rain on the 24th. That day was provisionally the joint sixth wettest day on record for the UK. Both storms produced gusts of 60 to 70mph in places, and the west coast of Scotland saw gusts above 80mph during Boelo. The last few days of the month were foggy in many areas, particularly the 30th and 31st.
The effect on generation was mixed. Storm days and the wet spells around them will have cut output sharply, because heavy cloud at this time of year gives panels very little to work with. Fog works the same way. A thick, slow-clearing morning fog can take out the best part of a short autumn day. If you saw an unexpected dip on the storm days, cloud is the likely cause.
Even so, the UK recorded 121% of its long-term average irradiance hours for October, and all four nations came in above average. The wet days were clearly broken up by brighter spells, and those bright days made up the difference. It’s worth keeping the context in mind, though. October is a low-light month, with shorter days and a lower sun, so 121% of an October average is a much smaller absolute number than 121% of a July average.
If you’re looking at your monitoring data, expect a patchy month, with strong days when the high pressure briefly built, sharp drops on the storm days and a flat finish as the fog set in. Sites in the south and east will have done better than the north and west for sunshine, as has been the case for most of this year.
From here, generation tapers into winter. Days are shortening quickly and the sun sits low in the sky, so output will keep falling through November and December, however good the weather is. That’s normal for a UK system and is already built into the annual yield numbers behind your project.
Source: https://www.metoffice.gov.uk/research/climate/maps-and-data/summaries
Ireland
October was stormy and wet across Ireland, but some eastern stations still recorded their sunniest October on record.
The first two weeks were changeable. Rain bands kept arriving from the west, heaviest there, with drier and brighter spells between them. The best run came from the 16th to the 19th, when high pressure settled over the country and brought mostly dry weather with sunny spells, plus the first air frost of the season on the 17th.
From the 20th, a string of deep low-pressure systems moved in, including the first two named storms of the season. Storm Austen hit the south and east on the 22nd and 23rd, and Storm Boelo hit the north and west on the 24th and 25th. Malin Head recorded a gust of 73 knots (135 km/h) on both days. Thick cloud and rain through that stretch will have taken output close to nothing at many sites.
The east did well for irradiance. Casement Aerodrome in Co Dublin recorded 137.5 hours, 135% of average and its sunniest October in 62 years of records. Dublin Airport had just three dull days all month. Shannon Airport finished right on its average, and Valentia Observatory in Co Kerry managed only 75.8 hours with 13 dull days. So, a site in Leinster will have had a much better October than one in the southwest or west.
Rainfall was 120% of average nationally, the 24th wettest October since 1941, with the northwest wettest. Newport in Co Mayo had 242.1mm, while Oak Park in Co Carlow had 83.4mm. Temperatures were above average everywhere, with a national mean of 11.41°C, 0.62°C above the 1991 to 2020 average. That’s nine months in a row above average, going back to February.
On your portal, look for a good run from the 16th to the 19th, sharp drops around the storms, and stronger numbers in the east than the west. Output will reduce now we enter the Winter months.
Source: https://www.met.ie/climate-statement-for-october-2026
