Date Published: 16/07/2025
Is it true that solar panels produce less energy in summer?
It might seem counter-intuitive, but heat and other factors can actually affect solar panel performance in the warmer months
Have you ever noticed or been told that solar panels can produce less energy during summer? At first glance, this sounds counter-intuitive. After all, summer means long sunny days and stronger sunlight – surely that’s ideal for
solar energy generation?
However, while it’s true that summer brings more sunshine hours, there are several reasons why solar panel performance might actually dip slightly during the hottest months.
Why does solar panel output drop in summer?
To understand this, it helps to quickly recap how solar panels work. Panels are made up of photovoltaic (PV) cells, which convert sunlight into electricity. The more sunlight they absorb, the more electricity they generate – but heat is a different story.
Here are the key reasons energy production may decrease in summer:
1. Higher temperatures reduce panel efficiency
Solar panels are designed to work best in direct sunlight, but high temperatures can reduce their efficiency. Most panels operate optimally around 25°C. As temperatures rise well above this, the voltage output of the panels drops, which leads to reduced power production. So, ironically, the very heat of summer can work against solar efficiency.
2. Stronger sunlight isn’t always better
Although summer brings longer daylight hours and more intense solar radiation, that doesn’t always result in proportionally more energy. Excessive heat can cause energy losses, and high-angle sunlight in the middle of the day can lead to reflection or scattering rather than absorption. So more sun doesn't automatically mean more electricity.
3. Panel angle and tilt may not be ideal
The sun sits higher in the sky during summer months. If solar panels are fixed and not adjusted seasonally, they might not be at the optimal angle to capture the sun’s rays directly. A poor angle can reduce how much solar energy is absorbed, even on a bright day.
4. Seasonal shading from vegetation
Increased plant and tree growth during summer can cause unexpected shading on solar panels. Even partial shading on one part of a panel can disproportionately reduce the output of the whole system. Keeping the area around panels clear of seasonal obstructions is important for maintaining performance.
5. Greater household energy demand
Many homes consume more electricity in summer due to air conditioning and fans. If the property’s consumption exceeds the output of the solar panels, it can appear as though the panels are underperforming, when in fact they’re simply unable to keep pace with high demand.
Should this put you off solar energy?
Not at all. Even though efficiency may dip slightly in very hot conditions, solar panels still produce significant amounts of electricity during summer. And over the course of a year, they remain one of the most sustainable and cost-effective ways to generate your own power.
The overall performance of solar systems depends on many factors, including location, panel quality, system design and installation. With modern technology and proper setup, the effects of summer heat can be minimised.
If you’re thinking about
switching to solar, it’s worth having your property assessed by a qualified installer who can recommend the best positioning, angle and system size for your needs.
Despite the seasonal quirks, solar power is a smart, long-term investment that keeps working for you all year round. You’ll reduce your electricity bills, cut your carbon footprint,
increase the value of your property and help move towards a greener future.
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