Each 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
For the first two weeks of August, weather continued where July left off. The middle of the month contained another extreme heat event, before returning to typical August temperatures.
The opening fortnight was dominated by the same high pressure that had defined July, particularly across southern parts. Daytime temperatures were high, rainfall was scarce and sunshine was plentiful. For solar systems in England and Wales, generation during this period will have been strong. Not quite at July’s extraordinary levels, but well above what a typical August delivers.
Around 10th to 14th August the heat intensified sharply. Parts of England and Wales hit heatwave conditions, and on 12th August Wales set a new record maximum temperature for August with 35.3°C recorded at Gogerddan. The following day, Kew Gardens in London provisionally reached 38.1°C. As with the heatwave periods we covered in May, June and July, the same caveat applies: panel efficiency does dip slightly above 25°C ambient temperature, and at 38°C outside, panel surfaces will have been considerably hotter still. But the clear skies and intense irradiance that come with that kind of high pressure more than offset the efficiency loss, and generation during this period will have peaked strongly.
From mid-month, the picture changed. Increasingly unsettled conditions pushed in from the west, bringing occasional heavy rainfall and thunderstorms across England and Wales. This shift will be visible in your monitoring data – a strong first half followed by a more variable second half as cloud cover started to interrupt generation.
The month closed with rainfall across the UK including heavy downpours in the final week, but most of the country still ended August with below average rainfall overall. The UK recorded 81% of its average August rainfall, with England and Wales the driest. Only northern Scotland and parts of central England came in above average.
The headline numbers confirm what the weather narrative suggests. The UK came in at 114% of its long-term average for irradiance, whilst England closed with its fourth warmest August on record for mean daily maximum temperature. The UK mean temperature was 1.4°C above the 1991–2020 average, making this the seventh consecutive month where the UK has recorded more than 1°C above the long-term average. Scotland and Northern Ireland were much closer to average, at +0.5°C and +0.7°C respectively, which aligns with the cloudier and wetter conditions those regions experienced.
For most customers in England and Wales, August will have delivered great generation. Not the record-breaker July was, but a month where the first half in particular continued to perform well above normal.
Source: https://www.metoffice.gov.uk/research/climate/maps-and-data/summaries
Ireland
August followed a similar pattern to the UK – a warm, largely settled first half that continued the summer’s strong run for solar generation, followed by a more unsettled finish as Atlantic low pressure finally reasserted itself.
The month opened with a brief unsettled spell as low pressure pushed up from the southwest, bringing outbreaks of rain and showers in the middle of the first week. High pressure re-established itself towards the end of that week and dominated through the second week, keeping conditions mostly dry away from the north and west. Then, around 12th August, high pressure shifted east and pulled a hot tropical continental airmass north over the country – the same setup that had produced Ireland’s record-breaking June and July temperatures.
Casement Aerodrome in Co Dublin hit 31.2°C on 12th August, the highest August maximum temperature ever recorded for a Dublin station in 127 years of records. Phoenix Park reached 30.9°C on the same date, Dunsany in Co Meath 30.5°C. Ten stations across the country broke their highest August daily minimum temperature record between 12th and 14th August.
For solar generation, this mid-month heat event was the standout period. Clear skies, strong irradiance and long late-summer days combined to push output well above what a typical August day delivers.
The third week cooled and clouded over as Atlantic low pressure from the northwest pushed closer, bringing rain and showers particularly to the north and west. The fourth week started dry again with high pressure briefly moving back over the country from the west, before a marked change from 25th August as low pressure from the south pushed widespread rain north. When the rain finally arrived on baked ground, some areas saw intense, localised downpours, with Phoenix Park recording 61.8mm in a single day on 27th August.
Irradiance for the month was variable by region, which is worth bearing in mind when looking at your monitoring data. Johnstown Castle in Co Wexford recorded 200.7 hours – its sunniest August since 2003. Shannon Airport came in at 152.7 hours, 107% of its long-term average. Casement Aerodrome recorded 153.1 hours, just fractionally below its long-term average at 99%. Malin Head in Donegal recorded just 101.3 hours, reflecting the cloudier conditions that the northwest experienced for much of the month. The south and east had the better of August for irradiance, continuing the regional pattern that held through most of the summer.
For most UrbanVolt customers in Ireland, your monitoring data through August will show strong output in the first half – particularly around that mid-month heat event – with a more variable second half as the unsettled conditions from late August took hold.
Source: https://www.met.ie/climate-statement-for-july-2026