Exposure to the sun is very good both for humans and of course for our cat companions, but if we do not protect them tomorrow they could have serious problems, such as skin cancer.
For this reason, if you are unfamiliar with the effects of the sun on a cat's skin, I encourage you to read this article where I will tell you about the benefits and drawbacks of letting them be exposed to the sun.
beneficial effects
Prevents or delays bone diseases
The sun helps us—yes, even humans—to synthesize vitamin D , without which we wouldn't be able to absorb calcium. A deficiency in this vitamin causes osteoporosis, rickets, and other bone-related problems.
Keeps them warm
Cats are warm-blooded animals, so they regulate their body temperature without problems after a certain age (around 5 or 6 months). But we do too, and yet we love to sunbathe to protect ourselves, even if just a little, from the cold 😉. So if we see them lying down in a part of the house where the sun's rays hit directly, the best thing we can do is leave them alone.
Damaging effects
If they are exposed to excess, they run the risk of having:
Burns
That's the first thing we'll look at. They can be superficial or deep burns . The former will be easier to heal, but the latter could become infected with bacteria and require veterinary care.
Solar or actinic dermatitis
If cats spend a lot of time exposed each day, their skin becomes inflamed and reddened. If the exposure is prolonged , the animals will experience itching and consequently scratch , causing wounds that could become infected.
Skin cancer
It is a disease caused by the abnormal growth of cells that have mutated, becoming malignant tumor cells. This is a process that doesn't happen overnight, but rather slowly. All cats are vulnerable, but those that are white or have white markings (ears, nose, and/or mouth) are at particular risk, since the absence or low content of melanin (which gives fur its color) increases the risk of developing this condition.
I hope this post has been useful to you  .