Learn how to care for your succulents when temperatures drop. Also, learn why forty degrees is considered a point of no returns for succulents. And what other temperatures can cause problems for these plants. The string of dolphin succulents will thrive in temperatures as low 40 degrees Fahrenheit during the colder months. However, they can be grown happily in summer temperatures up to 80 degrees Fahrenheit. Although this may seem labor-intensive, E. enopla can be difficult to find. If you already have the plant, you might consider collecting the seeds.