In general, foliage house plants grow best between 70 and 80 degrees Fahrenheit during the day and from 60 to 68 degrees Fahrenheit at night.
Most flowering house plants prefer the same daytime range but grow best at nighttime temperatures from 55 to 60 degrees Fahrenheit. The lower night temperature induces physiological recovery from moisture loss, intensifies flower color, and prolongs flower life.
Excessively low or high temperatures may cause plant failures, stop growth, or cause spindly appearance and foliage damage or drop. A cooler temperature at night is actually more desirable for plant growth than higher temperatures. A good rule of thumb is to keep the night temperature 10 to 15 degrees lower than the day temperature.