How much do solar panels generate if it is cloudy or raining

Is it worth it to install solar panels in winter?

When we are going to install solar panels, the first thing that comes to mind is: What happens to solar generation in winter? In these cases, we will continue to generate solar energy, although logically much less than if the sky is completely clear.

In Spain, which is in the northern hemisphere, it means that in winter there are much fewer hours of sunshine than in summer. For this reason, the production at the end of the day in summer compared to winter can be practically doubleHowever, all the production carried out by the panels will be energy that we will not be importing from the network, so we will continue to save a lot of money at the end of the month.

The efficiency of solar panels during the year is similar, although logically we cannot compare the solar production in summer where we have more than 14 hours of sun, compared to winter when we have less than 9 hours. In addition, one must also take into account the tilt of the sun above the horizonand it is that in winter the sun is “lower”, so this directly affects the solar irradiation in our panels.

Generally the Solar panels lose performance with high temperaturesthat is, in summer they can lose up to 15% yield due to heat. This is compensated with a greater solar irradiation and also with more hours of sun. This problem of high temperatures does not occur in winter, the downside is that we have fewer hours of effective sun, so at the end of the day we will be producing less.

It must be taken into account that a photovoltaic solar installation has a useful life of about 20 or 25 yearstherefore deciding not to install solar panels in winter doesn’t make much sense. If you install the panels in winter it will allow you to save on the electricity bill, it may not be up to 70% as in summer, but it is feasible to save approximately 30%, so the savings are there.

Solar production when there are clouds or it is raining

Many people wonder what happens when there are clouds or it is raining, and therefore there is no sun. The answer is that our solar panels continue to generate energybut logically not as much as if we had completely clear skies.

The Clouds can decrease solar production by up to 90%that is, if we have many black clouds in the sky and it is about to rain, the most normal thing is that the solar panels generate enough energy for normal home use using lights, TV, computer and little else. Nothing to do with the possibility of putting a dishwasher, washing machine or ceramic hob when the sky is completely clear.

If we have few clouds in the skyor they are very weak, it is possible that the production only drops 20% approximately, so that, if the installation has been adequately sized, we can continue cooking or putting the dishwasher without having to import power from the network.

In my home I have solar panels since mid-July 2022 with POWERwe are going to make a brief comparison of the production generated in the entire month of August, which was a record, and the production in November, which has been a very rainy month and with continuous clouds day after day.


  • Photovoltaic production: 708kWh


  • Photovoltaic production: 285kWh

As you can see, the differences between a month where there are many hours of sun and a month where there are fewer hours of sun, and also, it has been raining almost every week, are clear. However, with this production we have been able to self-consume 90% of the energy, so it is energy that we have not had to import from the grid.


Although it may seem that in winter it is not worth installing solar panels, the truth is that We will continue generating energy and saving on the electricity bill. Logically we are not going to produce the same in winter as in summer, both because of the hours of sunshine in summer, which are many more, and also, because generally in summer there are clear skies and no rain.

We must bear in mind that a photovoltaic solar installation is made to last between 20 and 25 years, and the objective is to amortize the installation as soon as possible, in addition to saving on the electricity bill month after month. Bearing this in mind, there are also electricity marketers that allow us to contract a virtual “battery”, with the aim that the kWh generated in summer can be discounted in winter since the solar production is lower, and in this way save more money. These types of companies are usually profitable if we have a very oversized solar installation in our home, that is, we have many more panels than we really need, and all the energy that we do not use is exported to the electricity grid.

It’s very important dimension the installation correctly, as companies like POWEN do. What other companies do is oversize the photovoltaic installation to pay less on the electricity bill, but the time it takes us to amortize these installations is clearly higher. What must be done is to adjust the photovoltaic installation to current electricity consumption needs, and also to future electricity consumption, in case you have children or buy an electric car.

Related Articles