Succulents enjoy being placed outdoors in summer – they will grow more vigorously and accumulate more reserves to help keep them healthy indoors over the winter. They can be moved outdoors once nighttime temperatures are above 10 to 12°C. To avoid burning them and causing permanent damage, however, it is essential to acclimatize them to the outdoors, protected from full sun, over a period of 10 to 14 days. You can do this by placing them in a shady corner and gradually moving them into sunnier spots (with morning or late-afternoon sun) and finally into full sun after about two weeks. You can also use a double layer of screen to filter the sunlight.
In late summer, bring your plants indoors when nighttime temperatures drop to about 8 to 10°C. Very spiny or hairy succulent plants (like Cephalocereus) tolerate colder temperatures and can be left outdoors later in the season. Finally, it is a good idea to systematically inspect the plants and soil before bringing them indoors and again two or three weeks later to detect any potential problems.