Our fair isle is known for its mixed bag of weather. We’re not blessed with year-round sunshine, which leaves many property owners wondering if solar panels are worth it.
Solar panels generate power even on cloudy and rainy days, making them a worthwhile investment for UK homeowners. While their output is reduced during grey weather, particularly in autumn and winter, they still provide enough electricity for significant energy cost savings.
In this article, we’ll explore solar panel efficiency in different weather conditions and seasons. Hopefully, this will provide some reassurance that solar panels are still a wise investment, even in the grey-old UK.
For advice on solar panel installation for your home or business, contact Cinergi, a trusted and accredited renewable energy expert serving the South of England. Contact us today using our online form or call us on 0333 257 3999.
Different weather conditions and their impact on solar panels
It’s true that the UK weather does play a big role in how efficiently solar panels work – but it’s not all doom and gloom! Let’s explore how various weather conditions impact how much electricity solar panels produce.
Cloudy weather
Cloudy days might seem like a solar panel’s worst enemy, but they can still produce electricity, even in particularly dense cloud cover. After all, the sun’s rays still penetrate clouds, as anyone who has been sunburnt on a cloudy day will tell you! You can expect output to dip by about a quarter on a day with light clouds.
Rainy weather
On a rainy day, energy output will dip to about the same level as when there is light cloud cover. However, rain can also be a friend to solar panels. It can help rinse off dirt, dust, and debris from the panels, and clean panels equal better efficiency.
Sunny weather
Bright, sunny days are when your panels are most productive for solar energy production. However, the efficiency of solar panels is affected by excessive heat. Solar Energy UK says solar power production falls by only 0.34% for every degree the temperature rises above 25°C. Even in the sunny South of England, this isn’t a great cause of concern.
Cold weather
It may be surprising, but as long as solar panels receive plenty of sunlight, they do well in cold temperatures. Cooler weather prevents panels from overheating, so they can generate electricity more effectively. A crisp, clear winter’s day could give you better results than you’d expect, although with fewer daylight hours, it still can’t rival a long, sunny summer’s day.
Snow
A light dusting of snow will melt quickly and have minimal impact on solar panels. Like rain, it can actually help clean them.
However, heavy snow can obstruct the photovoltaic cells, significantly reducing or even stopping the panels from producing energy. Once again, this is not a great cause of concern in the South of England, but something to consider if you live in a more northern area of the UK prone to heavy snow.
Windy conditions
Although wind often occurs on cloudy and rainy days, it doesn’t directly affect the amount of energy that solar panels generate. Light wind can even help by cooling solar panels and stopping them from overheating.
However, wind can also potentially damage your solar energy system. It’s crucial to ensure the panels are installed securely by a professional, accredited installer to withstand strong winds and ensure they are both safe and efficient.
How seasonal changes can impact solar panel efficiency
Autumn and winter
While solar panels work just as well in cold weather, solar power generation drops in the autumn and winter months as the nights draw in and daylight hours dwindle. According to a government report, in the winter, solar energy falls to an eighth of that of a warm June day.
However, for an average home in the South of England, this isn’t cause for concern. A 3.5 kW solar power system can generate around 3,000–3,500 kWh annually. Given that a three-bedroom house consumes around 2,700 kWh, solar energy is still a wise investment, even if your reliance on the grid may increase in winter.
Spring and summer
As mentioned above, hot temperatures can reduce the efficiency of solar panels. However, due to the number of daylight hours, more solar energy is produced in the summer months than at any other time of year.
According to Solar Energy UK, the peak performance of solar energy is at midday in April/May. So, in particularly sunny conditions, your solar PV system may generate more electricity than you actually need. That’s why it’s a savvy move to install an energy storage system like a Tesla Powerwall to store what you don’t use for use on more overcast days. You may even be able to sell your excess energy back to the National Grid via the Smart Export Guarantee (SEG).
Looking for solar panel advice? Contact us
Cinergi is a trusted, MCS-certified, and RECC member solar PV installer for the South Coast with over 40 years of expertise. Our independent, family-run business serves homes and businesses in Hampshire, Dorset, Wiltshire, and Surrey. As independent installers, we offer friendly, honest advice and exceptional service.
Contact us today to get a solar panel quote for your home or business.
Thanks to everyone at Cinergi on a great job – we couldn’t be happier with the solar generation system and the staff were helpful, transparent, friendly and knowledgeable at all stages. We’d happily recommend Cinergi to friends and will be in touch in the future to install an Air Source Heat Pump.
Chris Zardis
Frequently asked questions about the effect of weather on solar panels
Solar panels will continue working in extreme temperatures, but they are most effective between 20°C and 25°C. Efficiency starts to decrease slightly above 25°C, but only minimally, which is not a real concern for UK property owners.
Solar panels can still work well in winter in the UK, even with less sunlight. Although they produce less electricity in lower light conditions, they can still generate enough to make them a good year-round investment.
No, you should not cover your solar panels in winter as it will block the solar cells and prevent them from generating electricity.
The worst months for solar panel performance in the UK are typically December and January, when daylight hours are at their lowest. However, solar panels can still generate electricity during these months. While you may have to supplement your energy supply with electricity from the grid, they do offer year-round savings.
