What will El Niño mean for solar power?

There has been plenty of talk about the "super El Niño" developing in 2026. But what will it mean for solar panels, their efficiency and the electricity they generate?

For homeowners, the question is fairly straightforward. Will it help you get more out of your solar panels?

The answer is, unsurprisingly, it depends.

El Niño is a warming of waters in the tropical Pacific that changes weather patterns around the world. The October outlook points to an exceptionally strong event continuing into early 2027. But that doesn't mean everyone will experience the same weather. Source: Columbia University's October outlook

Some places could see conditions that help solar generation. Others could see more cloud and rain.

And in households that experience hotter weather, electricity use could increase at the same time.

Power generation depends on where you live

El Niño affects different areas differently. Your location and the time of year will matter much more than a headline about rising global temperatures.

Parts of southern Africa and north-east Australia face a greater risk of drought during this event. For the UK, the Met Office has highlighted an increased chance of wetter, stormier weather in autumn and early winter. Source: Met Office

For solar panels, the question is how much sunlight actually reaches the roof.

If your area gets clearer skies, generation could increase. If it gets more cloud, generation could fall. Dry weather alone doesn't guarantee a better result. Our guide to solar panels on cloudy days explains how much cloud costs you, and solar panels in autumn covers what a wetter, stormier season means for a British roof.

For UK homeowners, there is no reliable basis for assuming El Niño will bring a bumper solar year. Its effects on UK weather are less direct and harder to predict. Source: Government Office for Science

More heat doesn't mean more efficiency

This is an important distinction.

Solar panels use sunlight to generate electricity. As their cells get hotter, they generally become less efficient at converting that sunlight into power. Source: US Department of Energy

That means a hot, sunny day can still produce plenty of electricity. But the panels may generate less than they would under the same sunlight at a lower cell temperature. We go through the numbers in do solar panels work in a heatwave?

So if El Niño brings more sunshine to your area, there could be a benefit. Higher temperatures may offset some of it.

The amount will depend on your panels and the conditions on your roof.

Cleaning panels may become more important

Where the weather becomes drier and dustier, keeping an eye on your panels makes sense.

Dust, pollen and bird droppings can stop some sunlight reaching the cells. With less rain to wash them away, that build-up may become more noticeable.

But this doesn't mean every homeowner needs to start cleaning their panels more often.

In the UK, rain usually does much of the work. Whether additional cleaning is worthwhile depends on your roof and the amount of dirt collecting on it. Follow your manufacturer's advice and use a professional where access is difficult. Source: Energy Saving Trust

If you need advice, see our guide to cleaning and maintaining solar panels.

Your electricity use may go up too

For some households, any increase in solar generation could arrive alongside an increase in electricity use.

As temperatures rise, fans and air conditioning may run for longer. That means more demand for power to keep the home comfortable. If that sounds like your house, solar panels and air conditioning looks at how well the two pair up.

Some of this demand could happen while your panels are generating, allowing you to use more of your home-grown electricity straight away.

But cooling may continue into the evening, when solar generation falls.

So don't assume that generating more electricity will automatically mean a lower bill. How much you use, and when you use it, will matter too.

Batteries could help you use more of what you generate

A battery can store surplus solar electricity for use later, including after sunset. That can help households make more use of their own generation. Source: Energy Saving Trust

The key word here is surplus.

If your home uses most of its solar electricity during the day, there may be relatively little left to store. If you regularly export electricity and then buy it back in the evening, storage could be more useful.

You don't necessarily need a battery large enough to store a whole day's generation. The right size depends on how much electricity you have left over and how much you need later.

The cost of the battery, storage losses and your import and export tariffs also affect the benefit. El Niño alone isn't a reason to buy one.

See what size solar battery do I need? to understand what storage could mean for your home, and how long does a solar battery last? for what you are paying for over its life.

What could this mean for a home in London?

For a London household, a useful starting point is how solar generation and electricity use change throughout the year.

Solar generationHousehold use

Month	Solar generation (kWh)	Household use (kWh)
Jan	160	270
Feb	210	260
Mar	350	250
Apr	460	230
May	490	200
Jun	490	190
Jul	500	180
Aug	440	190
Sep	390	200
Oct	270	230
Nov	190	250
Dec	150	260
Year	about 4,100	about 2,700

Solar panels generally generate more electricity in summer than winter. A battery can move some of that electricity from daytime into the evening, but ordinary home batteries cannot carry summer's surplus through to winter. Source: Energy Saving Trust

That seasonal pattern is more useful for planning than assuming El Niño will deliver extra sunshine. The summer and winter guides walk through each end of it, and how much sun does my roof get? plots the same monthly curve for your own roof rather than an illustrative one.

For homeowners, the practical steps are straightforward. Keep track of generation, check for dirt or unexpected drops in performance, and understand when your household uses electricity.

El Niño may change the weather. The benefit to your solar panels will depend on what happens where you live.

Frequently asked questions

Will El Niño make my solar panels generate more electricity?

Not necessarily. El Niño changes weather patterns, and the effect on solar output comes down to how much sunlight reaches your roof. Clearer skies would help, more cloud would hurt. For the UK, the Met Office points to a wetter, stormier autumn and early winter, and the government's own assessment says the effects on UK weather are indirect and hard to predict. There is no reliable basis for expecting a bumper solar year.

Do solar panels work better in hot weather?

No. Panels run on light, not heat. As the cells get hotter they become slightly less efficient at turning sunlight into electricity, so a hot, sunny day still produces plenty of power but a little less than the same sunlight would at a cooler temperature. Any gain from extra sunshine can be partly offset by the heat that comes with it.

Should I clean my solar panels more often during El Niño?

Only if dirt is actually building up. In the UK, rain does most of the cleaning on a pitched roof. A drier spell can let dust, pollen and bird droppings accumulate, so keep an eye on the panels and your monitoring app. Follow the manufacturer's advice and use a professional where access is difficult.

Is El Niño a reason to buy a solar battery?

On its own, no. A battery earns its keep by storing surplus electricity you would otherwise export and buy back later. Whether that adds up depends on how much you have left over, when you use electricity, your tariffs and the cost of the battery. Those things matter far more than one weather pattern.

Related

• Do solar panels work on cloudy days?
• Do solar panels work in a heatwave?
• Solar panels in autumn: rain, wind and storms
• Do solar panels need cleaning in the UK?
• Solar panels and air conditioning in the UK
• What size solar battery do I need?
• How much sun does my roof get?
• Savings calculator