Solar performance 2025 so far – how do you stack up?

The UK’s Solar Performance in 2025: A Comprehensive View

The first eight months of 2025 in the United Kingdom presented a mixed picture for solar energy generation, characterized by a gloomy and wet start to the year followed by a remarkably warm and sunny summer. The performance of solar panels was directly influenced by these contrasting weather patterns, highlighting the significant impact of cloud cover and rainfall on energy output.

A Gloomy Start (January – March)

The year began with below-average temperatures and varied rainfall. While January saw UK-wide rainfall at 79% of the long-term average, there were significant regional differences, with some areas experiencing very heavy rain and flooding. The Met Office’s February report indicated a drier-than-average month overall, but with “extensive areas of low cloud” that would have limited solar irradiation. March continued this dry trend for most of the country, with England experiencing its sixth driest March on record. Despite the lack of rain, cloud cover remained a factor, limiting potential solar gains.

A Sunny and Dry Spring (April – May)

April and May marked a significant shift in weather patterns. April was noted for being particularly sunny and dry, with the UK recording just over half its normal rainfall. This trend continued into May, which was provisionally the second sunniest May on record for the UK. During this period, southern England saw less than half its average rainfall, and all nations recorded more than 100% of the average long-term sunshine. These conditions were ideal for solar generation, likely leading to a strong performance for solar installations across the country.

A Summer of Extremes (June – August)

The summer of 2025 proved to be a mixed bag. June was an average month for rainfall, but with a clear north-south divide; Scotland and Northern Ireland were wetter than average, while southern England was drier. However, the period from July to August was particularly favorable for solar power. July saw strong sunshine hours and relatively low rainfall. August was a month of warmth and sunshine, with the UK’s mean temperature provisionally 1.2°C above the long-term average. Sunshine hours were notably high, reaching 112% of the long-term average. Rainfall was highly variable, with Scotland being wetter while England was significantly drier, receiving just 42% of its average rainfall. The mid-August heatwave, in particular, would have led to peak solar performance in central and southern regions.

Renewable Energy Industry Insights (2025)

According to the Annual Renewables Report and other industry analyses, 2025 is a pivotal year for the UK’s renewable energy sector. The government’s Clean Power 2030 Action Plan aims to achieve 95% clean energy by 2030. Key findings from recent reports include:

Solar Approvals: While the number of solar PV projects granted planning permission fell by 19% in the 12 months leading up to Q1 2025, the total approved energy capacity rose by 16%, reaching a 16-year high.
Generation Mix: As of June 2025, zero-carbon sources (including wind, solar, nuclear, and hydro) provided 61% of Britain’s electricity, the highest June share in recent years. Solar generation, in particular, reached its highest June contribution in the last five years, providing 12% of the total electricity.
Overall Production: The UK’s energy production from primary fuels fell to a record low in 2024. Primary electricity (wind, solar, and hydro) accounted for 19% of this total.
Public Attitudes: A DESNZ Public Attitudes Tracker from Spring 2025 shows that solar energy remains the most supported renewable option among the public, with 86% overall support.

Weather Conclusion

The first half of 2025 presented a challenge for solar performance due to persistent cloud cover and intermittent rain, particularly at the beginning of the year. However, this was more than offset by the exceptional amount of sunshine and low rainfall experienced during the latter half of the spring and throughout the summer. The data from the Met Office and renewable industry reports indicates that solar performance in the UK for the first eight months of 2025 was likely robust, with high output during the sunnier months compensating for the earlier, cloudier periods.

Weather Data Tables

Here is the cloud cover and precipitation data from the met office.

Cloud Cover Categories in UK

Fraction	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Cloudier	70%	66%	63%	57%	53%	50%	45%	47%	51%	59%	68%	71%
Clearer	30%	34%	37%	43%	47%	50%	55%	53%	49%	41%	32%	29%

Daily Chance of Precipitation in UK

Days of	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Rain	8.4d	6.5d	7.1d	6.6d	7.4d	7.9d	7.6d	7.4d	6.9d	8.6d	8.3d	8.3d
Mixed	0.2d	0.2d	0.1d	0.0d	0.0d	0.0d	0.0d	0.0d	0.0d	0.0d	0.0d	0.1d
Snow	0.1d	0.1d	0.0d	0.0d	0.0d	0.0d	0.0d	0.0d	0.0d	0.0d	0.0d	0.0d
Any	8.7d	6.9d	7.2d	6.7d	7.4d	7.9d	7.6d	7.4d	6.9d	8.6d	8.4d	8.5d

Renewable Energy Contribution: As of June 2025, zero-carbon sources (including wind, solar, nuclear, and hydro) provided 61% of Britain’s electricity. This was the highest share for that month in recent years.

Solar Contribution: Solar generation reached its highest June contribution in the last five years, providing 12% of the total electricity for that month.

How you may have performed – UK domestic solar production.

Based on the information available from the Met Office, government reports, and renewable energy data providers, here is a detailed comparison of monthly solar yields in the UK over the past three years (2023, 2024, and 2025).

For this comparison, we will use a hypothetical “average” domestic solar installation, which is a 4 kWp system, a common size for a typical three-bedroom home in the UK.

Monthly Solar Yield Comparison (kWh)

This table provides an estimated monthly yield for an average 4 kWp domestic solar system. Note that actual yields can vary significantly based on location, panel orientation, and shading.

Month	2023 Yield (kWh)	2024 Yield (kWh)	2025 Yield (kWh)*
Jan	80	100	110
Feb	110	120	135
Mar	220	250	290
Apr	300	320	360
May	350	360	410
Jun	380	400	450
Jul	360	380	420
Aug	330	340	380
Sep	200	220	Data not yet available
Oct	120	140	Data not yet available
Nov	70	85	Data not yet available
Dec	60	65	Data not yet available

Monthly Solar Production: Positive and Negative Factors

January

Positives: The 2024 and 2025 yields were significantly higher than 2023. This was driven by a warmer and sunnier start to the year in 2024, and a particularly sunny January in 2025.
Negatives: As the month with the fewest daylight hours and a high likelihood of cloud cover, January consistently has the lowest solar yields of the year.

February

Positives: Similar to January, the yields for 2024 and 2025 were notably higher than 2023, due to more favorable weather conditions. The days are lengthening, leading to a natural increase in production.
Negatives: Still a low-yield month compared to the rest of the year due to shorter days and high cloud cover in some regions.

March

Positives: Production begins to ramp up significantly as daylight hours extend. The Met Office reported a record-breaking March in 2025, which would translate into exceptional solar output. The dry and sunny conditions were highly favorable.
Negatives: While a strong month, production is still highly dependent on the number of clear days, and can be impacted by late winter cloudiness or snow events in some parts of the UK.

April

Positives: April is a consistently strong month for solar production. Both 2024 and 2025 saw very high yields driven by sunny and dry conditions. The angle of the sun is increasingly high in the sky, optimizing panel efficiency.
Negatives: Sudden shifts to cloudy, showery weather can temporarily reduce yields.

May

Positives: Historically, one of the best months for solar. May 2025 was provisionally the second sunniest May on record, leading to outstanding yields. The long daylight hours and high sun angle are ideal.
Negatives: Potential for intermittent cool and wet spells that can hinder production.

June

Positives: The peak month for daylight hours. June 2025 was particularly strong, with a record-breaking mean temperature and high sunshine. This would have led to peak yields for the year.
Negatives: High temperatures can sometimes slightly reduce a solar panel’s efficiency (a phenomenon known as the temperature coefficient), although this is a minor effect compared to the benefit of long daylight hours.

July

Positives: Excellent yields due to long daylight hours and the height of the sun in the sky. July 2025, with its strong sunshine hours, would have been a strong performer.
Negatives: Often prone to more unsettled weather and thunderstorms compared to June, which can lead to higher cloud cover and reduced production.

August

Positives: A reliably high-production month. The August 2025 heatwave would have pushed production to its yearly peak in many parts of the country.
Negatives: Days begin to shorten, and the sun’s angle starts to descend, leading to a slight drop from the peak of June and July.

September – December

Positives: September can still provide good yields, particularly at the beginning of the month. As we move into October, the cooler temperatures can slightly boost the efficiency of the panels on a clear day.
Negatives: Production drops off dramatically each month due to the reduction in daylight hours, lower sun angle, and increasing cloud cover. Storms and heavy rainfall are more frequent, severely limiting solar generation. By December, yields are at their lowest point of the year.